SOLUTION: Place the indicated product in the proper location on the grid. (x^2 + 4)(x^2 - 4)

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Place the indicated product in the proper location on the grid. (x^2 + 4)(x^2 - 4)      Log On


   

Question 625271: Place the indicated product in the proper location on the grid.
(x^2 + 4)(x^2 - 4)
Answer by jsmallt9(3758) About Me  (Show Source):
You can put this solution on YOUR website!
One could just use FOIL to multiply this. But it's faster if you realize that
%28x%5E2+%2B+4%29%28x%5E2+-+4%29
exactly matches the pattern of the left side of
%28a%2Bb%29%28a-b%29+=+a%5E2-b%5E2
with the "a" replaced by x%5E2 and the "b" being replaced by "4". So, according to the right side of the pattern, the product will be:
%28x%5E2%29%5E2-%284%29%5E2
which simplifies to:
x%5E4-16

P.S. You get the same answer if you use FOIL correctly.