Răspuns :
1
-2a+4b+4c=-2x3+4(b+c)
=-6+20
=14
2
a+X=12,-a+X=c
-ab+Xb+ac+Xc=-ab+ac+Xb+Xc
=-a(b+c)+X(b+c)
=-ax18+Xx18
=18(a+X)
=18x12
=216
-2a+4b+4c=-2x3+4(b+c)
=-6+20
=14
2
a+X=12,-a+X=c
-ab+Xb+ac+Xc=-ab+ac+Xb+Xc
=-a(b+c)+X(b+c)
=-ax18+Xx18
=18(a+X)
=18x12
=216