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