foil method solve for x

Question

(X + 1)(a - 4) = y -2   Solve the equation for X

 

Do i do foil method so then I end up with 

 

ax - 4x + a - 5 = y -2 (?) 

 

Or am I off? How do I break this down to solve for x ?

Answer 1

You're on the right track.First, do foil, but remember to multiply the 1 and the -4. I think you subtracted 1 from -4.

 

(x + 1) (a - 4) = y - 2 --> ax - 4x + a - 4 = y -2

 

Then, add 4 to both sides: ax - 4x + a = y + 2

 

Next, subtract a: ax - 4x = y - a + 2 ... and simplify: (a-4)x = y - a + 2

 

Now, divide by a-4 to isolate x: x = (y - a + 2) / (a-4)

 

Cancel out the a from the fraction: x = (y+2) / (-4) --> x = - (y-2) / 4 [negative y-2 over 4]

 

Pretty sure that should work.