Question

чему равно значения выражения 0.9x-(0.7x+0.6y)если, 3y-x =9?

Answer 1

0.9x - (0.7x + 0.6y) = 0.9x - 0.7x - 0.6y = 0.2x - 0.6y = -0.6y  + 0.2x = -0.2(3y-x)
3y-x = 9
-0.2*9 = -1.8