Question

2(ab+ac+bc),где a =5,b=4,c=10

Answer 1

2(ab+ac+bc),где a =5,b=4,c=10;/// 2(20+50+40)=2*110=220

Answer 2

2(ab+ac+bc)=2ab+2ac+2dc=2×5×4+2×5×10+2×4×10=40+100+80=220