A+B+C+D+E=180X(5-2)=540 .1
C+E=2B .2
A-B=20 A=20+B.3
A=1/2D 20+B=1/2D D=40+2B.4
2 3 4代入1得
20+B+B+2B+40+2B=540
6B=480
B=80
A=20+B=100
A+B+C+D+E=180X(5-2)=540 .1
C+E=2B .2
A-B=20 A=20+B.3
A=1/2D 20+B=1/2D D=40+2B.4
2 3 4代入1得
20+B+B+2B+40+2B=540
6B=480
B=80
A=20+B=100