Question

Срочно??!!Дам 20баллов. Номер 5

Answer 1

$\star \; \; x^2\pm px+q=(x\pm \frac{p}{2})^2-(\frac{p}{2})^2+q\; \; \star \\\\\\x^2-8x+15=(x-4)^2-16+15=(x-4)^2-1\; ;\\\\(x-4)^2-1=(x-4-1)(x-4+1)=(x-5)(x-3)\; .$