Question

Factorize: $x^2-10x+21$.

Answer 1

Factorize ${\mathit{x}}^{\mathbf{2}}\mathbf{-}\mathbf{10}\mathit{x}\mathbf{+}\mathbf{21}$.

We can write the expression as

$x^2-10x+21=x^2-7x-3x+21$

$=x\left(x-7\right)-3\left(x-7\right)$ [ Taking common terms out ]

$=\left(x-3\right)\left(x-7\right)$

Hence, the factored expression is $\left(x-3\right)\left(x-7\right)$.