Question

Dau coroana!Stiind ca:
b+c=21 si a=7,calculati a.b+a.c
b-c=31 si a.b-a.c=837,calculati a
a.b-a.c=1440 si a=45,calculati b-c
a+b-c=48 si d=144:(95-83),calculati a.d+b.d-c.d
Vreau si explicatia nu numai rezultatul.va rog!

Answer 1

axb+axc=a(b+c)=7x21=147
axb-axc=837
a(b-c)=837
31a=837
a=27
axb-axc=1440
a(b-c)=1440
b-c=1440:45
b-c=32
axd+bxd-cxd=d(a+b-c)=144:(95-83)x48=576