Question 675494
3a+b=3
2a-5b=-15
...
b = 3-3a
2a - 5(3-3a) = -15
2a - 15 + 15a = -15
17a = -15 + 15 
17a = 0
{{{highlight_green(a = 0)}}}
...
3(0) + b = 3
{{{highlight_green(b = 3)}}}
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