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