Pre Calculus
posted by Anonymous .
So I only have 3 homework questions left and I can't seem to figure out how to solve. I've tried solving them, but I keep getting them wrong. Any help?
Factor the polynomials:
a) 3x^2 +19x  40
b) x^4  25x^2
Simplify the expression completely:
(1/(xh)^3  1/x^3)/8h

b. Difference of two squares, then one of those factors can be factored as a difference of two squares again. I can check your work.
a. What is ( x+8)(3x5)
c. do some combination.
((x^3(xh)^3)/(8h(x^3*(xh)^3)
now factor the numerator as a difference of two cubes. Doing it in my head, I see some reduction. 
ooh, nevermind I figured out how to do a) answer is 3(x5)(x+8)....I forgot to move the 3 over
and b) uses the difference of squares formula so the answer is x^2(x5)(x+5)
still can't figure out the third one though!