(1B) The product $(a+b)(c+d)$
Practice
Expand and simplify.
*Write your answers with powers of $x$ in descending order. $\left(\square x^2 \pm \square x \pm \square\right)$
$\left(x-9\right)\left(x+2\right)$
$\left(x+6\right)\left(x-7\right)$
$\left(x-4\right)\left(2+x\right)$
$\left(-x+1\right)\left(-9+x\right)$
$\left(-1+x\right)\left(-x+1\right)$
$\left(-8+x\right)\left(-x+7\right)$
$\left(9-x\right)\left(4-x\right)$
$\left(1-x\right)\left(-7+x\right)$
$\left(-2x+3\right)\left(7x-8\right)$
$\left(6x+5\right)\left(3x+5\right)$
$\left(-2x+5\right)\left(-7+6x\right)$
$\left(x+8\right)\left(7-4x\right)$
$\left(6+7x\right)\left(2x-3\right)$
$\left(8-3x\right)\left(2x+1\right)$
$\left(-1+2x\right)\left(-6+5x\right)$
$\left(1+7x\right)\left(1+5x\right)$