Question

Afla numerele necunoscute: 25+a÷(20+4×28-4)=39; 52×5+b=124×3+25×4; 20+3×12+c+=148; d-2×(480×2-90÷10)+5=75

Answer 1

25+a÷(20+4×28-4)=39;
a÷(20+112-4)=39-25
a÷ 128=14
a=128×14
a=1792


52×5+b=124×3+25×4;
260+b=372+100
b=472-260
b=212

20+3×12+c=148
20+36+c= 148
c=148-56
c= 92

d-2×(480×2-90÷10)+5=75
d-2×(960-9)+5=75
d-2×951+5=75
d-1902+5=75
d=1902+75-5
d=1972