Question

(580-x):4=100... 40:x+70=90

Answer 1

1. х=180 (100 умножаем на 4; 580-400=180)
2. х=2 (от 90 отнимаем 70; 40:20=2)

Answer 2

1)
(580-x):4=100
(580-x)=100×4
(580-x)=400
580-x=400
x=580-400
x=180
2)
40:x+70=90
40:x=90-70
40:x=20
x=2