Question

What quadrant do the solutions lie in?
1) 3x – 2y = 10
5x + 3y = 4 A) I
2) 3x + 2y = 14
x – 3y = –10 B) II
3) x + 2y = 8
4x + 6y =22 C) III
4) 2x + 3y = –12
4x – 2y = –2 D) IV

Answer 1

graph the pair of lines and see where the intersection lies in

Answer 2

I have trouble solving these equations.

Answer 3

Systems ... do you know how to solve systems of EQ?

Answer 4

Kind of

Answer 5

are you allowed to use a graphing calc at school?

Answer 6

I do online school.

Answer 7

http://www.wolframalpha.com/input/?i=3x+%E2%80%93+2y+%3D+10+%2C+5x+%2B+3y+%3D+4%09

Answer 8

would you like me to show you how to solve systems of equations?

Answer 9

1) 3x – 2y = 10
5x + 3y = 4
-> (2, -2) in the fourth quadrant

Answer 10

I want to know the main key point in knowing how to solve problems like this.

Answer 11

http://www.khanacademy.org/video/systems-of-equations?topic=systems-of-eq-and-ineq

Answer 12

points*

Answer 13

you're looking for the intersection of the two lines ... to find this you can use Substitution Method, Elimination Method, Graphing Method or Matrices

Answer 14

Okay, I've herd of Substitution Method. What do you do for this step?

Answer 15

Solve for one of the variables ... y = .....

Answer 16

2) 3x + 2y = 14
x – 3y = –10
-> (2, 4) in the first quadrant!

Answer 17

and plug it in the second equation and solve for x

Answer 18

try solving for y in the first eq 1st system

Answer 19

What do you plug in?

Answer 20

Random numbers?

Answer 21

did you solve for y?

Answer 22

No

Answer 23

let's do that first:

Answer 24

3) x + 2y = 8
4x + 6y =22
-> ( -2, 5) in the second quadrant

Answer 25

do you know how to solve for y?

Answer 26

Nope

Answer 27

ok ... here we go :

Answer 28

3x-2y =10

Answer 29

subtract 3x from both sides

Answer 30

-2y = 10-3x

Answer 31

divide by -2

Answer 32

y= -5 +3/2x

Answer 33

4) 2x + 3y = –12
4x – 2y = –2
-> ( -15/8, -11/4) in the third quadrant!

Answer 34

this is solving for y... now we have an expresion for y we can substitute y in the second eq with the expression for y we just found

Answer 35

5x+3y=4 substitute the y with -5+3/2x

Answer 36

we get : 5x + 3(-5+3/2 x) = 4 ...

Answer 37

solve for x

Answer 38

5x-15 +(9/2)x=4

Answer 39

Here I like the same denominator ...(10/2)x -30/2 +(9/2)x=8/2

Answer 40

now eliminate the denominator

Answer 41

10x-30+9x=8

Answer 42

combine like terms

Answer 43

19x =38 -> x=2

Answer 44

substitute 2 in y=-5+(3/2)x , y=-5+3 =-2 the solution (2,-2)...(IV quad)

Answer 45

watch the video ...I think you'll understand better

Answer 46

also use iTunes U for algebra videos ...awesome resource

Answer 47

are you still here ?

Answer 48

Yeah I'm here :-)

Answer 49

Thanks for helping me understand this a little bit better.

Answer 50

good ... did you understand ?

Answer 51

use khanacademy ... Sal is good at explaining

Answer 52

Lol okay :-)

Answer 53

have fun ... <3Math