Question

100: *2=40
80: *7=70

Answer 1

$100: x*2=40$
$100:40=x*2$
$2.5=x*2$
$x=2.5:2$
$x=1.25$
Ответ: 1.25

$80:x*7=70$
$80:x=70:7$
$80:x=10$
$x=80:10$
$x=8$
Ответ: 8

Answer 2

100:5*2 = 40; 
80/8*7 = 70;