Question

Помогите с 8 , 11 и 12 примерами !!!

Answer 1

$8); ; frac{1}{4}a^2+6a+9=0\\D=36-4cdot frac{1}{4}cdot 9=27\\a_1=frac{-6-3sqrt3}{1/2}=-12-6sqrt3; ,; ; a_2=-12+6sqrt3\\frac{1}{4}a^2+6a+9=frac{1}{4}cdot (a+12+6sqrt3)cdot (a+12-6sqrt3)\\11); ;  frac{1}{9}-frac{b}{3}+frac{b^2}{4}=(frac{b}{2}-frac{1}{3})^2 \\12); ;  frac{x^2}{49}-frac{2x}{7}+1=(frac{x}{7}-1)^2$