Question 374044
3a-3b=-15
-3a-3b=-3 add
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-6b=-18
b=-18/-6
b=3 ans.
3a-3*3=-15
3a-9=-15
3a=-15+9
3a=-6
a=-6/3
a=-2 ans.
Proof:
-3*-2-3*3=-3
6-9=-3
-3=-3