Question

Aflati pe :a,b,c,d din egalitățile:

a) (2xa-18):5=20;
b) (16+bx2)x25=400;
c) (88-70:c)x10=180;
d) 3x(99+d)-100=275

Answer 1

a) 2×a-18=20×5
(2×a)-18=100
2×a=100+18
2×a=118
a=118/2
a=59
b) (16+b×2)×25=400
16+b×2=400/25
16+b×2=16
b×2=16-16
b×2=0
b=0/2
b=0
c) (88-70/c)×10=180
88-70/c=180/10
88-70/c=18
88-18=70/c
70=70/c
c=70/70
c=1
d)3×(99+d)=275+100
3×(99+d)=375
99+d=375/3
99+d=125
d=125-99
d=26

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