Question

Solve the system by substitution.
{2.5x - 3y = -13
{3.25x - y = -14

I usually have no problem with the substitution method, but this one is stumping me.

Answer 1

I started working on it, then got stuck.

Answer 2

solve the bottom equation for y

y = 3.25x+14

plug y into the top equation. solve for x. then plug the x value into either equation to get y.

Answer 3

I started it that way by solving for y. I multiplied the y equation by -3 to cancel out the y

Answer 4

but then somwhere after that it got messed up.

Answer 5

are you still stuck on it?

Answer 6

yes

Answer 7

ok gimme a sec and lemme work it out

Answer 8

ok

Answer 9

3.25x -y = -14
y = 3.25x+14

2.5x-3y = -13
2.5x-3(3.25x+14)= -13
2.5x-9.75x-42= -13
-7.25x = 29
x= -4

Answer 10

tomo's explaining it.

Answer 11

plug x back into the original equation of: {3.25x - y = -14

Answer 12

oh ok, I did it wrong then I think. I started with 3.25x - y = -14 and multiplied the equation by -3;

-3(3.25x - y = -14)
= -9.75x +3y = 42

Answer 13

yeah thats solving by elimination is what you're trying to do.

Answer 14

ohhhh oops. so x = -1

Answer 15

tomo said that x = -4

Answer 16

I I mean y = 1 and x = -4

Answer 17

y = 1 and x = -4

Answer 18

yes thats correct (:

Answer 19

good job!

Answer 20

yay thanks!

Answer 21

no problem! :D