Question 712193
2a+3b=7
-2a+b=13 add
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4b=20
b=20/4
b=5 ans.
2a+3*5=7
2a+15=7
2a=7-15
2a=-8
a=-8/2
a=-4 ans.
Proof:
-2*-4+5=13
8+5=13
13=13