Question

Решите два уравнения.

Answer 1

• $\frac{5x-2}{x+2}=\frac{6x-21}{x-3}\\(5x-2)(x-3)=(6x-21)(x+2)\\5x^2-17x+12=6x^2-9x-42\\x^2+8x-54=0\\D=64+216=280=(2\sqrt{70})^2\\\left.\begin{array}{cc}x_1=-4+\sqrt{70}&x_2=-4-\sqrt{70}\end{array}\right.$

• $\frac9{x+3}=2x-1\\9=(2x-1)(x+3)\\2x^2+5x-12=0\\D=25+96=121=11^2\\x_1=\frac{-5-11}4=-4\\x_2=\frac{-5+11}4=1.5$