Work only with the second equation at the beginning. Solve for x for it.
7x - 2x = 3 Combine the left hand side.
5x = 3 Divide by 5
5x/5 = 3/5 Do the division
x = 3/5 = 0.6
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Now work with the top equation.
3(0.6) + 5y = 13 Multiply on the left.
1.8 + 5y = 13 Subtract 1.8 from both sides.
1.8 - 1.8 + 5y = 13 - 1.8 Do the subtraction
5y = 11.2 Divide by 5
5y/5 = 11.2/5
y = 2.24 Answer