Solving a system of equations {ACT}

If x + y = 26 and x - y = 18, then y = ?
A.)  4
B.)  8
C.)  9
D.)  22
E.)  44

x + y = 26
x - y = 18
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2x = 44   {added the two equations together, eliminating the y}
x = 22   {divided each side by 2}

x + y = 26   {top original equation}
22 + y = 26   {substituted 22, in for x, into top original equation}
y = 4   {subtracted 22 from each side}

A.)  4

- Algebra House