Question

se stie ca: x+y=23 si z=15. calculati xz+yz

Answer 1

x+y=23
z=15
xz+yz=?

z(x+y)=15*13=195

Answer 2

$\displaystyle x+y=23 \\ z=15 \\ xz+yz=z(x+y)=15 \times 23=345 \\ \boxed{xz+yz=345}$