Question

descompuneti in factori suma x patrat-10x+21

Answer 1

$x^2-10x+21 \\ =\left(x^2-3x\right)+\left(-7x+21\right) \\ =x\left(x-3\right)-7\left(x-3\right) \\ =\left(x-3\right)\left(x-7\right)$