Question

уровнение 90-60:х=87

Answer 1

$90 - \frac{60}{x} = 87 \\ - \frac{60} {x} = 87 - 90 \\ - \frac{60}{x} = - 3 \\ \frac{60}{x} = 3 \\ 3 x = 60 \\ x = 20$

Answer 2

90-60:х=87
90-60/х=87
-60/х=87-90
-60/х=-3
60=3х
3х=60
х=20