Question

afla termenul necunoscut: 9×7-a=5×7; b+10×3=8×8; 91-(c+3×9)=6×8; d-7×8=9×4

Answer 1

a) 9×7-a=5×7
=63-a=5×7
=63-a=35
= - a =35-36
= - a =- 28
 a = 28
 b)
b+10×3=8×8
=b+30=8×8
=b+30=64
b=64-30
b=34
c)
91=(c+3×9)=6×8
91-(c+27)=6×8
91-c-27=6×8
64-c=6×8
64-c=48
-c=48-64
-c=-16
c=16
 d)d-7×8=9×4
d-56=9×4
d=56=36
d=36+56
d=92