Question 179186
2x+4y=40 multiply by 3
7x-3y=4 multiply by 4 & add
6x+12y=120
28x-12y=16
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34x=136
x=136/34
x=4 ans.
2*4+4y=40
8+4y=40
4y=40-8
4y=32
y=32/4
y=8 ans.
Proof:
7*4-3*8=4
28-24=4
4=4