Evaluate: 7x^2-20x-3

Expression: $7{x}^{2}-20x-3$

Write $-20x$ as a difference

$7{x}^{2}+x-21x-3$

Factor out $x$ from the expression

$x \times \left( 7x+1 \right)-21x-3$

Factor out $-3$ from the expression

$x \times \left( 7x+1 \right)-3\left( 7x+1 \right)$

Factor out $7x+1$ from the expression

$\left( 7x+1 \right) \times \left( x-3 \right)$