SOLUTION: Not sure what book this comes from. Please help. Given P(x)=x^2-4x, find and simplify P(a+h)-P(a). I get (x+2)(x-2). I think I'm supposed to substitute something somewhere. H

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Not sure what book this comes from. Please help. Given P(x)=x^2-4x, find and simplify P(a+h)-P(a). I get (x+2)(x-2). I think I'm supposed to substitute something somewhere. H      Log On


   



Question 44791: Not sure what book this comes from. Please help.
Given P(x)=x^2-4x, find and simplify P(a+h)-P(a).
I get (x+2)(x-2). I think I'm supposed to substitute something somewhere. How do I work this? Thank you!

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Given P(x)=x^2-4x, find and simplify P(a+h)-P(a)
To get P(a+h) substitute "a+h" in place of "x", as follows:
P(a+h)=(a+h)^2-4(a+h)
=a^2+2ah+h^2-4a-4h
To get P(a) substitute "a" in place of "x", as follows:
P(a)=a^2-4a
Now subtract P(a) from P(a+h), as follows:
P(a+h)-P(a)=2ah+h^2-4h
Cheers,
Stan H.