Substitution method

How do you solve these with the substitution method?
4x - y = -14
y = 8x + 7

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4x - (8x + 7) = -14   {substituted 8x + 7, in for y, into top equation}
4x - 8x - 7 = -14   {distributed negative sign through parentheses}
-4x - 7 = -14   {combined like terms}
-4x = -7   {added 7 to both sides}
x = 7/4   {divided both sides by -4}

y = 8x + 7   {bottom original equation}
y = 8(7/4) + 7   {substituted 7/4, in for x, into bottom equation}
y = 14 + 7   {cancelled and multiplied}
y = 21   {added}

x = 7/4 and y = 21

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