Question

Помогите пожалуйста !!!

Answer 1

4.
$frac{2x-y}{x+y} : frac{2x-y}{x-y} *frac{x+y}{x-y} = frac{2x-y}{x+y} * frac{x-y}{2x-y} *frac{x+y}{x-y} = \ \ = frac{1}{x+y} * frac{x-y}{1} *frac{x+y}{x-y} = frac{1}{1} * frac{x-y}{1} *frac{1}{x-y} = frac{1}{1} * frac{1}{1} *frac{1}{1} = 1$

при любых х и у

5.
$frac{1-2x}{3} + frac{2-3x}{4}+ frac{x}{5} = frac{1}{12} \ frac{20(1-2x)}{20*3} + frac{15(2-3x)}{15*4}+ frac{12x}{12*5} = frac{5*1}{5*12} \ frac{20-40x}{60} + frac{30-45x}{60}+ frac{12x}{60} = frac{5}{60} \ 20-40x+30-45x+12x = 5 \ 50-73x=5 \ -73x=-45$
x=45/73