Question

7.Se stie ca:x+y=23 si z=15.Calculati xz+yz
8.Se stie ca:x-y=12 si z=10.Calculati xz-yz
9.Se stie ca:ab+ac=420 si b+c=14.Aflati a

Answer 1

7) x+y=23  si  z=15
xz+yz=(x+y)*z=23*15=345
8)  x-y=12  si z=10
xz-yz=(x-y)*z=12x10=120
9) ab+ac=420   si b+c=14  a=?
 a*(b+c)=420
a*14=420
a=420:14
a=30