Question

Va rog,va dau coroana,am nevoie urgent,va rog frumos

ex : 3,4,5 ..va rog mult​

Answer 1

3)a=7 b+c=15 b-c=7

ab+ac=? ab-ac?

ab+ac=a(b+c)=7x15=105

ab-ac=a(b-c)=7x7=49

4)a=7 b+c+d=70

ab+ac+ad=a(b+c+d)=7x70=490

5)a=3 b+c+d=30 3a+2(ab+ac+ad)=3a+2a(b+c+d)=3x3+2x3x30=

=9+180=189