X÷(450-390)=4 39-x=49÷7 56÷x=800:100 (360÷6)÷x=4
Х÷(450-390)=4 х÷60=4 х=60*4 х=240 39-х=49÷7 39-х=7 х=39-7 х=32 56÷х=800:100 56÷х=8 х=56÷8 х=7 (360÷6)÷х=4 60÷х=4 х=60÷4 х=15