2A+4B=36 4A+2B=42 A=? B=?

Question

求解释啊！

Answer 1

2A+4B=36 (1)
4A+2B=42 (2)
(2)÷2，得
2A+B=21(3)
(1)-(3),得
3B=15
B=5
A=(36-4×5)÷2=8
所以
A=8， B=5

Answer 2

2A+4B=36 (1)
4A+2B=42 (2)
(1)+(2)
6A+6B=78
A+B=13
4A+B=52 (3)
(3)-(1)
2A=16
所以
A=8
B=13-A=5

Answer 3

2A+4B=36
4A+2B=42

4A+8B=72
4A+2B=42

6B=30,B=5,A=8

Answer 4

4A+8B=72
4A+2B=42得：6B=30 ,B=5
A=8，B=5
采纳吧

Answer 5

2（2A+4B）=4A+8B=72 两个算式一剪，6B=30,所以B=5,A=8