seeing structure in expressions common core - Factor x^{3} - 729

Anonymous (last edited 4 years ago)

STEP 1: Recall what an expression is

STEP 2: Recall the formula for the difference of cubes.

STEP 3: Simplify the expression

The expression x^{3}+ 729 can be written as

x^{3} + 9^{3}

Since a^{3}+b^{3} = (a+b)(a^{2}-ab + b^{2})

Substituting a = x and b = 9 into the formula yields:

x^{3} + 729 = (x+9)(x^{2} - 9x + 81)