Answer
$x-7$
Work Step by Step
RECALL:
(1) $(a+b)(c+d) = ac +ad + bc + bd$ (known as the FOIL method)
(2) $(a-b)(a+b)=a^2-b^2$
Use the formula (1) above to multiply the first pair of factors, and use formula (2) to multiply the second pair of factors to obtain:
$=[1\cdot2 + 1\cdot(-x) + x \cdot 2 + x\cdot(-x)] -(3^2 - x^2)
\\=(2 -x+2x-x^2)-(9-x^2)
\\=(2+x-x^2)-(9-x^2)$
Subtract each term of the subtrahend to obtain:
$=2+x-x^2-9-(-x^2)
\\=2+x-x^2-9+x^2$
Combine like terms to obtain:
$=(2-9)+x+(-x^2+x^2)
\\=-7+x
\\=x-7$
