Question

{X+2Y/2+3X-Y/3=5{0.2(X+2Y)+0.8(3X-Y)=4

Answer 1

令a=x+2y

b=3x-y

a/2+b/3=5 (1)

0.2a+0.8b=4 (2)

所以a=20-4b

代入(1)

10-2b+b/3=5

5b/3=5

b=3

a=20-4b=8

所以x+2y=8 (3)

3x-y=3 (4)

(4)×2+(3)

7x=14

x=2

y=3x-3=3