Question

5x+2y=-3 3x+3y=9 what's the value of X and Y?

Answer 1

step1; multiply first equation with 3
step2; multiply second equation with -2
step3; add the two equations
see what you get

Answer 2

i don't get it when you say multiply them together? Isn't it add or subtract the opposites?

Answer 3

i never said multiply the equations

Answer 4

alright. when you said multiply first equation with 3, though can you explain what you mean?

Answer 5

you'll get 15x + 6y = -9

Answer 6

so, then subtract 15x from -9?

Answer 7

or would i subtract 6?

Answer 8

when he said "multiply the first equation by 3", he means

5x+2y=-3

3(5x+2y)=3(-3 ) ... Multiply both sides by 3.

15x + 6y = -9 ... distribute

Answer 9

So

5x+2y=-3

turns into

15x + 6y = -9

Answer 10

Ohhhh, i got it now (: thank you so much for clearing that up!

Answer 11

Now multiply both sides of the second equation by -2

3x+3y=9

-2(3x+3y)=-2*9

-6x - 6y = -18

Answer 12

This means that

5x+2y=-3
3x+3y=9

becomes

15x + 6y = -9
-6x - 6y = -18


The whole reason we did all this was to add up the equations so one variable cancels out. Notice how 6y + (-6y) = 0y and that goes away leaving you to be able to solve for x

Answer 13

so x=-9 and y=-18?

Answer 14

no that's not correct

Answer 15

Add the two equations

15x + 6y = -9
-6x - 6y = -18
----------------
9x + 0y = -27


9x = -27

x = ???

Answer 16

x=3

Answer 17

closer, but still no

Answer 18

ohh, -3 ahaha

Answer 19

better, now use that to find y

Answer 20

so plug in -3 to 2y=-3? making it -6=-3 dividing that and making it 2?

Answer 21

pick any equation where there's an x and y

so I'm picking the first one

5x+2y=-3

5(-3)+2y=-3 .. plug in x = -3

-15+2y=-3

2y = -3 + 15

2y = 12

y = 12/2

y = 6

So the solutions are x = -3 and y = 6

Answer 22

They form the ordered pair (-3, 6)

Basically, the two lines cross at the point (-3, 6)

Answer 23

thank you!

Answer 24

you're welcome