Solve y = 3x – 12 by the substitution method.
2x – 3y = -13

Question

Solve y = 3x – 12 by the substitution method.
2x – 3y = -13

shane_b · Answer

Ok that's pretty simple.  

The first equation is already in terms of y since it's "y=3x-12".  Place (3x-12) any place you see a "y" in the second equation...then solve the second equation for x.  

Once you know x, place its value back into one of the equations and solve for y.

shane_b · Answer

We can do it step by step if you like...

anonymous · Answer

yes please

mathteacher1729 · Answer

Here is a great video on solving systems of linear equations by substitution: http://youtu.be/cwHR_B9zK7k

shane_b · Answer

Ok.  Here are the original equations:
y = 3x – 12 
2x – 3y = -13

Substitute y in the second equation with 3x-12:
2x – 3(3x-12) = -13

Solve that equation for x to get x=7.  Now that you know what x is, place it back into one of the original equations and solve for y:

y=3(7)-12

Solving for y you get y = 9.

anonymous · Answer

ok..

anonymous · Answer

thanks!

shane_b · Answer

yw :)