Question

(5+7)x²-(5+8)x+1=0


Найти корень уравнения.

Answer 1

Смотри..................

Answer 2

$\displaystyle \tt (5+7)x^2-(5+8)x+1=0\\\\ \displaystyle \tt 12x^2-13x+1=0\\\\ \displaystyle \tt D=(-13)^2-4\cdot12\cdot1=169-48=121\\\\ \displaystyle \tt \sqrt{D}=\sqrt{121}=11\\\\ \displaystyle \tt \bold{x_1}=\frac{13+11}{2\cdot12}=\frac{24}{24}=\bold{1}\\\\ \displaystyle \tt \bold{x_2}=\frac{13-11}{2\cdot12}=\frac{2}{24}=\bold{\frac{1}{12}}$