Question

Выполните действия
(√x+√xy)²
(4√5-7√5)²

Answer 1

(√х+√ху)²=x+xy+2√x√xy=x+xy+2x√y
(4√5-7√5)²=16*5+49*5-2*4√5*7√5=80+245-280=45

Answer 2

$1)(\sqrt{x} +\sqrt{xy} )^{2}=(\sqrt{x} )^{2} +2*\sqrt{x}*\sqrt{xy}+(\sqrt{xy})^{2}=x+2x\sqrt{y}+xy\\\\2)(4\sqrt{5}-7\sqrt{5} )^{2} =(-3\sqrt{5} )^{2}=(-3)^{2} *(\sqrt{5})^{2}=9*5=45$