Question

ПОМОГИТЕ РЕШИТЬ ПРИМЕР
ПОЖАЛУЙСТА
( даю много баллов )

Answer 1

$\displaystyle\bf\\\frac{9c-100d}{3\sqrt{c}-10\sqrt{d} } -7\sqrt{d} =\frac{(3\sqrt{c} )^{2} -(10\sqrt{d})^{2} }{3\sqrt{c}-10\sqrt{d} } -7\sqrt{d} =\\\\\\=\frac{(3\sqrt{c} -10\sqrt{d} )\cdot(3\sqrt{c}+10\sqrt{d} ) }{3\sqrt{c} -10\sqrt{d} } -7\sqrt{d} =3\sqrt{c} +10\sqrt{d} -7\sqrt{d} =\\\\\\=3\sqrt{c}+3\sqrt{d} } =3\cdot(\sqrt{c} +\sqrt{d} )\\\\\\\sqrt{c} +\sqrt{d} =77,51\\\\\\3\cdot(\sqrt{c} +\sqrt{d} )=3\cdot 77,51=232,53\\\\\\Otvet : \ 232,53$