What is Y=4x+3 Y=2x-8 using substitution

Question

I need help I forgot how to do substitution.

Answer 1

We have 2 equations

 

y = 4x+3

y = 2x-8

 

Since both equations are equal to y, substitute one for the y of the other.

 

2x-8 = 4x+3

 

We can now solve for x

 

-2x=11

x = -5.5

 

Now evaluate either equation for y at x=-5.5

y = 2x-8

y = 2(-5.5)-8

y = -11-8 = -19