Question

Daca xy+xz-5x=60 si x=6,calculeaza 3y+3z

Answer 1

x(y+z)-5•6=60
x(y+z)-30=60
x(y+z)=90
6(y+z)=90
y+z=90:6
y+z=15
=> 3(y+z)=15•3=45