Question

Daca x*y=30 si x*z=25, sa se calculeze x*(y+z) si x*(y-z)

Answer 1

x*(y+z) =x*y +x*z =30+25=55

x*(y-z)= x*y-x*z= 30-25=5

Answer 2

xy=30
xz=25

calculaţi x(y+z) ,

dar xy+xz=x(y+z)
⇒x(y+z) = 25+30 = 55 . 

x(y-z) = xy-xz 
         = 30-25
          = 5 .