ПОМОГИТЕ! 1) 18+(16-Х)*8=90 2) (4900:Y-280):60=7

Question

ПОМОГИТЕ!
1) 18+(16-Х)*8=90
2) (4900:Y-280):60=7

Answer 1

18+(16-x)×8=90
(16-x)×8=90-18
128-8x=72
-8x=72-128
-8x=-56
8x=56
x=56÷8
x=7
18+(16-7)×8=18+9×8÷18+72=90

(4900÷y-280)÷60=7
4900÷y-280=7×60
4900÷y=420+280
4900÷y=700
y=400÷700
y=7
(4900÷7-280)÷60=(700-280)÷60=420÷60=7