Answer
$x^2+17x+72$
Work Step by Step
RECALL:
For any real numbers a, b, and c:
$a(b+c)=ab + ac$
Use the distributive property (which is shown above) to obtain:
$=x(x+8) + 9(x+8)
\\=x(x) + x(8) + 9(x) + 9(8)
\\=x^2+8x+9x+72
\\=x^2+(8+9)x+72
\\=x^2+17x+72$
