Question 295209
Solve each system by substitution: 
(a) 5x + y = 10
3x – 3y = 6
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1st: Solve the 1st equation for "y":
y = 10-5x
2nd:
Substitute for "y" in the 2nd equation and solve for "x":
3x - 3(10-5x) = 6
3x -30+15x = 6
18x = 36
x = 2
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3rd: Since y = 10-5x, solve for "y":
y = 10-5*2 = 0
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Solution: (2,0)
Check your answer in the two original equations.
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(b) y = 13x + 14
x = y - 1 
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1st: The 2nd equation is already solved for x,
so substitute for "x" in the 1st equation:
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y = 13(y-1) + 14
y = 13y-13+14
y = 13y +1
12y = -1
y = -1/12
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2nd: Since x = y-1
x = (-1/12)-1
x = -13/12
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Cheers,
Stan H.