Question

найдите значение выражения x2 , -х2, (-х)2, если х=5;-4​

Answer 1

$x=5:\; \; x^2=5^2=25\; \; ;\; \; -x^2=-5^2=-(5^2)=-25\; \; ;\\\\(-x)^2=(-1\cdot x)^2=+1\cdot x^2=x^2=5^2=25\\\\\\\\x=-4:\; \; x^2=(-4)^2(-1\cdot 4)^2=+4^2=16\; \; ;\; \; -x^2=-\underbrace{(-4)^2}_{16}=-16\; ;\\\\(-x)^2=x^2=(-4)^2=16$