Question

calculati folosind factorul comun
a)82+96×82+97×18
b)27×101-27
c)14×(x+y)-5×(x+y)
d)(a+b)×(b+c)×(c+a)-(a+b)×(b-c)×(a+c)

Answer 1

a)82×(1+96)+97×18=82×97+97×18=97×(82+18)=97×100=9700

b)27×101-27=27×(101-1)=27×100=2700

c)14×(x+y)-5×(x+y)=(x+y)×(14-5)=9×(x+y)

d)(a+b)×(b+c)×(c+a)-(a+b)×(b-c)×(a+c)=

=(a+b)×(a+c)×[(b+c)-(b-c)]=

=(a+b)×(a+c)×(2c)