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