Question

Decide whether the given ordered pair is a solution to the system of equations.

y = x − 9
x + y = −1
(4, −5)

Answer 1

x+ y = 9

x - y = -1

The easiest way to solve this is using the elimination method. Let's add the two equations:

x + y = 9

x - y = -1

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2x + 0 = 8

2x = 8

x = 4

To find y:

x - y = -1

x + 1 = y

4 + 1 = y

5 = y