Question

Solve the system of equations by substitution. What is the solution for x?

2x + y = 1
4x + 2y = -1

Answer 1

@cram

Answer 2

@SolomonZelman

Answer 3

I have ten minutes left on this test, and I have three questions to ask on here :)

Answer 4

you have to first try to get a variable by itself.
2x + y = 1 (subtract 2x from both sides)
y = -2x + 1

now sub -2x + 1 in for y in the other equation..
4x + 2y = -1
4x + 2(-2x + 1) = -1
4x - 4x + 2 = -1
2 = -1 (incorrect)

this problem has NO SOLUTION

Answer 5

Can you help me with a couple more?

Answer 6

ask away...you don't have much time

Answer 7

Determine which system below will produce infinitely many solutions.

2x + 5y = 24
2x + 5y = 42

Answer 8

2x + 5y = 24
2x + 5y = 42

3x - 2y = 15
6x + 5y = 11

4x - 3y = 9
-8x + 6y = -18

5x - 3y = 16
-2x + 3y = -7

Answer 9

-8x + 6y = -18 ---- reduce by dividing by 2
-4x + 3y = -9 -- multiply by -1 to make x positive
4x - 3y = 9

same as other equation...so infinite solutions
answer is 3rd one

Answer 10

Choose the equivalent system of linear equations that will produce the same solution as the one given below.

6x + 2y = -6
3x - 4y = -18

12x + 4y = -12
15x = -30

8x + 4y = -4
14x = -10

6x - 8y = -36
-6y = -42

6x - y = -15
3y = 9

Answer 11

crap...I read this wrong...do you mean the same solution as the first one ?

Answer 12

What?

Answer 13

Its the same kind of problem you did before

Answer 14

I had to submit it

Answer 15

no its not....produce the same solution as what ?
Oh...I am so sorry.

Answer 16

Wait its letting me do a question? lol.. Whatever its this one


Choose the equivalent system of linear equations that will produce the same solution as the one given below.

6x + 2y = -6
3x - 4y = -18

12x + 4y = -12
15x = -30

8x + 4y = -4
14x = -10

6x - 8y = -36
-6y = -42

6x - y = -15
3y = 9

Answer 17

Oh its the same quetion.. Well its letting me do it again, just this question to improve my score. so lets go for it!

Answer 18

6x + 2y = -6 -- reduce
3x + y = - 3
y = -3x - 3

3x - 4y = -18
3x - 4(-3x - 3) = -18
3x + 12x + 12 = -18
15x + 12 = -18
15x = -18 - 12
15x = -30
x = -2

y = -3x - 3
y = -3(-2) - 3
y = 6 - 3
y = 3

solution is (-2,3)
-----------------------
12x + 4y = -12 -- reduce
3x + y = -3
y = -3x - 3

15x = -30
x = -2

y = -3x - 3
y = -3(-2) - 3
y = 6 - 3
y = 3

solution is (-2,3)
---------------------
your first two sets of equations have the same solution

Answer 19

so what answer choice?

Answer 20

I think the question was asking what has the same solution as the first set of equations....if that is the case, then the answer is : 12x + 4y = -12....15x = -30, because the first one is what you are comparing the answer to

Answer 21

Ah ok :)

Answer 22

sorry it took so long

Answer 23

I got a 90! :)

Answer 24

WHOOP - WHOOP...doing the happy dance now. Way to go :)

Answer 25

haha I am going to be doing a ton of assignments because I thought my class ended 9/8, not 8/8 and I have 20 assignments left. can you help me? I am doing 10 today. now 9. Can you help with a few atleast?

Answer 26

are they math ?

Answer 27

yes

Answer 28

close this post and ask your questions

Answer 29

we can still keep typing even though this question is closed

Answer 30

Alright I closed it

Answer 31

Which of the following inequalities matches the graph?

graph of an inequality with a solid horizontal line through the origin and shading below the line

x less than or greater to 0

x greater than or equal to 0

y less than or greater to 0

y greater than or equal to 0

Answer 32

solid line means it has an equal sign.....horizontal line through the origin means x will always be 0. Shading below the line means less then.

answer : y < = 0 ....its gonna be answer 3.....it should read less then or equal, not greater.

Answer 33

Which correctly describes how the graph of the inequality -4y - x ≥ 7 is shaded?

Above the solid line

Below the solid line

Above the dashed line

Below the dashed line

Answer 34

-4y - x >= 7
-4y >= x + 7 -- when dividing by negative, the sign changes
y <= -1/4x - 7/4

if there is an equal sign, it will be a solid line

< less then means shading below the line

so answer is : Below solid line

Answer 35

Which of the following inequalities matches the graph?

graph of an inequality with a solid line through the points (0, -2) and (2, 1) with shading above the line

3x - 2y greater than or equal to 4

3x - 4y less than or greater to 2

3x - 2y less than or greater to 4

The correct inequality is not listed.

Answer 36

slope = (y2 - y1) / (x2 - x1)
slope = (1 - (-2) / (2 - 0)
slope = 3/2

y = mx + b
(2,1)...x = 2 and y = 1
slope = 3/2

1 = 3/2(2) + b
1 = 3 + b
1 - 3 = b
-2 = b

y = 3/2x - 2 --- multiply by 2
2y = 3x - 2 -- subtract 3x from both sides
-3x + 2y = -2 -- multiply by -1 to make x positive
3x - 2y = 2

solid line means there is an equal sign. Shading above the line means greater then.
answer is : Correct one is not listed. It should be 3x - 2y >= 2

Answer 37

Which inequality matches the graph?

X, Y graph. X range is negative 10 to 10, and Y range is negative 10 to 10. Dashed line on graph has positive slope and runs through negative 10, negative 9 and negative 1, negative 3 and 8, 3. Above line is shaded.

-2x + 3y > 7

2x - 3y < 7

-3x + 2y ≥ 7

3x - 2y ≤ 7

Answer 38

Dashed line does not contain an equal sign...so last 2 answers are eliminated.

-2x + 3y > 7
3y > 2x + 7
y > 2/3x + 7/3
positive slope

-2x + 3y < 7
3y < 2x + 7
y < 2/3x + 7/3
positive slope

above line shading means greater.....so answer is : first one

Answer 39

Which of the following inequalities matches the graph?

graph of an inequality with a solid vertical line through the point (5, 0) and shading to the left of the line

x less than or greater to 5

x greater than or equal to 5

y less than or greater to 5

y greater than or equal to 5

Answer 40

solid vertical line passing through (5,0)....this means x willl always be 5.
I am having trouble with this one....I am sorry

Answer 41

kk next one

Answer 42

I know its gonna be less then

Answer 43

Lincoln Middle School has a total of $200 to spend on notebooks and tablets for the school board meeting. Notebooks cost $7.00 each, and tablets cost $5.00 each.

If x represents the number of notebooks and y represents the number of tablets, which graph correctly shows the solution to the problem?

X, Y graph. X range is negative 60 to 60, and Y range is negative 60 to 60. Solid line on graph has negative slope and runs through 0, 40 and 50, negative 30. Below line is shaded.

X, Y graph. X range is negative 60 to 44, and Y range is negative 60 to 60. Solid line on graph has negative slope and runs through 0, 40. Above line is shaded.

X, Y graph. X range is negative 60 to 44, and Y range is negative 60 to 60. Dashed line on graph has negative slope and runs through 0, 40. Above line is shaded.

X, Y graph. X range is negative 60 to 44, and Y range is negative 60 to 60. Dashed line on graph has negative slope and runs through 0, 40. Below line is shaded.

Answer 44

I think it will be x <= 5

Answer 45

thats for the last question

Answer 46

7x + 5y < = 200
5y <= -7x + 200
y <= -7/5x + 40

It contains a solid line because of the equal sign
It has a negative slope
y intercept is (0,40)

answer is : I think it is the first one

Answer 47

I am so sorry but I have to go now. I hope I was able to help some. Good-bye for now.

Answer 48

Wait! Theres on emore problem!

Answer 49

lets have it

Answer 50

The networking organization you joined is throwing a party. You are in charge of buying the chips, which cost $2.50 per bag and salsa, which costs $4.00 per jar. The chips & salsa budget you are given totals $60. The inequality 2.5x + 4y 60 represents the possible combinations of chips (x) and salsa (y) you can buy.

graph of the inequality 2.5 x plus 4 y is less than or equal to 60

Which of the following does not represent a solution to the inequality?

10 bags of chips and 2 jars of salsa

20 bags of chips and 2 jars of salsa

14 bags of chips and 5 jars of salsa

18 bags of chips and 6 jars of salsa

Answer 51

When will you be back? lol you are like my hero.

Answer 52

2.5x + 4y <= 60
x = chips and salsa = y
now we sub in our answer choices and see which ones are correct.

2.5(10) + 4(2) <= 60
25 + 8 <= 60
33 <= 60 (correct)

2.5(20) + 4(2) <= 60
50 + 8 <= 60
58 <= 60 (correct)

2.5(14) + 4(5) <= 60
35 + 20 <= 60
55 <= 60 (correct)

2.5(18) + 4(6) <= 60
45 + 24 <= 60
69 <= 60 (incorrect)

answer is the last one.
That figures....I had to do all the others to find this out...lol

I will probably be back on tonight sometime...sorry that I can't give you a definite time.

Answer 53

I have to go now, but I will hopefully catch you later

Answer 54

I got a 70 By the way. thatll have to do! Ill do the three assignments on my own and hopefully you can make a dent with me in the night assignments!