9)a=2b
b=c/4
c=d-10
d=2e
d+e=75 2e+e=75 3e=75 e=75:3=25
d=2e=2×25=50
c=d-10=50-10=40
b=c/4=40/4=10
a=2b=2×10=20
nr sunt
a=20
b=10
c=40
d=50
e=25
10)
7-[5200:10-5 ×(360-2 × x)]:20=5
-[520-5 ×(360-2 × x)]:20=5-7
-[520-5 ×(360-2 × x)]:20=-2
[520-5 ×(360-2 × x)]=2×20
-5 ×(360-2 × x)=40-520
-5 ×(360-2 × x)=-480
5 ×(360-2 × x)=480
(360-2 × x)=480:5
360-2 × x=96
-2 × x=96-360
-2 × x=-264
2 × x=264
x=264:2=132
