Question

se stie ca x+y=23 z=15 xy+yz

x-y=12 z10 xz-yz

ab+ac=420 b+c =14 a =?

ab-ac =135 a =9 b-c =?
va rog !!!!!

Answer 1

xz+yz=z(x+y)=15*23=345
xz-yz=z(x-y)=10*12=120
a(b+c)=420     a*14=420     a=420:14    a=30
a(b-c)=135  9*(b-c)=135    b-c=135:9     b-c=15