Question

(B-5)x2=30 si
[2x(d-30)-45]x3=165

Answer 1

(B-5)x2=30
B-5=30:2
B-5=15
B=15+5
B=20

[2x(d-30)-45]x3=165
[2x(d-30)-45]=165:3
2x(d-30)-45=55
2x(d-30)=55+45
2x(d-30)=100
d-30=100:2
d-30=50
d=50+30
d=80