Question

Maria wants to solve the following system using the elimination method:

4x + 9y = 59
x + y = 17

What number should the equation x + y = 17 be multiplied by to eliminate y?


9
4
–4
–9

Answer 1

Medals!

Answer 2

Maria wants to solve the following system using the elimination method:

4x + 9y = 59
x + y = 17

What number should the equation x + y = 17 be multiplied by to eliminate y?


9
4
–4
–9

Answer 3

Do you know how to use the elimination method?

Answer 4

The work of a student to solve a set of equations is shown below:

Equation 1: x + 2y = 10
Equation 2: 2x + 5y = 15
Step 1: –2(x + 2y) = –2(10)
2x + 5y = 15

Step 2: –2x – 4y = –10
2x + 5y = 15

Step 3: 1y = 5

Step 4: x + 2(1) = 10

Step 5: x = 8


In which step did the student first make an error? (4 points)


Step 3
Step 4
Step 2
Step 1

Answer 5

this is the second question can someone explain

Answer 6

im not really good at elimination can u show me

Answer 7

Give me a sec

Answer 8

okay

Answer 9

x+2y=10
2x+5y=15

In order to eliminate a term the need to cancel each other out, I used the x term as it was the easiest.
-2*x+2y=10 becomes -2x-4y=-20
So now we have
-2x-4y=-20
2x+5y=15

Add those together and what do we get?

Answer 10

do i have to substitute?

Answer 11

Not for elimination method, the point of elimination method is to find the value for a variable by eliminating all other variables. In this case we want to solve for y so we have to get rid of the x on the top and bottom. Since the x on the bottom is positive we have to make the x on top negative so when we add them we get 0x.

Answer 12

1y = -5

Answer 13

1y = -5
1y 1y Divide
= -5

Answer 14

so the answer is Step 2 right?

Answer 15

Almost, we are trying to isolate the y not remove it also in this case you could write it as y=-5 as all variables have an inferred 1 in front of them

Answer 16

Explain why.

Answer 17

because he has –2x – 4y = –10 When the - 10 has to be -20

Answer 18

Spot On!

Answer 19

1y = 5 it should be -5

Answer 20

it is asking for the First error

Answer 21

Yes, indeed it should be y=-5

Answer 22

so which one should I choose?

Answer 23

it is asking for the first error which is the –2x – 4y = –10
2x + 5y = 15

Answer 24

it should be -20

Answer 25

Correct

Answer 26

so the answer is Step 2?

Answer 27

I believe you just answered your own question :-)

Answer 28

Can u help me with last one?

Answer 29

Jill wants to solve the following system using the elimination method:

y = x + 8
y = 3x – 11

What number should the equation y = x + 8 be multiplied by to eliminate x?

Answer 30

I am trying to do it but cant get to an answer

Answer 31

–1
3
–3
–2

Answer 32

What is x in this equation 5-x=0

Answer 33

y = x + 8

Answer 34

-1?

Answer 35

What I mean is in 5-x=0 what must x be to make this statement true?

Answer 36

5 -5 = 0

Answer 37

x =5

Answer 38

3-3 = 0 so the answer is 3?

Answer 39

y = x + 8
y = 3x – 11

Now what must x equal to cancel the positive 3 out?

Answer 40

Im not sure

Answer 41

I think your over thinking this, it's basic addition/subtraction what must happen to have x=0
3+x=0

Answer 42

-3 is the answer right?

Answer 43

Correct

Answer 44

okay thank you very much

Answer 45

No problem, if you need anymore help I would also look on Khan Academy they have resources like this video pretty good stuff helped me get through a lot of my math classes

https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-systems-topic/cc-8th-systems-elimination/v/addition-elimination-method-1

Answer 46

Of course don't hesitate to ask either :P

Answer 47

I will for sure use that thanks alot