Question

Вопрос на фото НА ФОТО

Answer 1

1.

$25^{x-3} =frac{1}{125} \\5^{2(x-3)}=5^{-3}\\2(x-3)=-3\\2x-6=-3\\2x=-3+6\\2x=3\\x=1.5$

2.

$sqrt{frac{2}{5x-18}} =frac{1}{6} \\frac{2}{5x-18} =frac{1}{36} \\2*36=5x-18\\5x-18=72\\5x=90\\x=18$

3.

$log_{11} (21-10x)=2\\11^{2} =21-10x\\121=21-10x\\-10x=100\x=-10$