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How do you solve the system $x - 2 y = 14$ $x − 2y = 14$ and $x + 3 y = 9$ $x + 3y = 9$ by substitution?

1 Answer

May 24, 2015

Replace one of the variables in one of the expressions with its value from the other expression and then solve.

x - 2y = 14 means that x = 14 + 2y
x + 3y = 9 means that (14 +2y) + 3y = 9
5y = 9 - 14 = -5
y = -1
x = 14 +2y = 14 - 2 = 12

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