Question

Which order pair is a solution of the equation y= x -2

A-(3,1)
B-(1,3)
C-(-1,3)
D-(3,-1)

Answer 1

(3,1) y= x -2,  when x = 3, y = 3 -2 = 1 ....YES
(1,3) y= x -2 , when x = 1, y = 1 -2 = -1 ....NO
(-1,3) y= x -2 , when x = -1, y = -1 -2 = -3 ....NO
(3,-1) y= x -2 , when x = 3, y = 3 -2 = 1 ....NO

answer is 
A-(3,1)

Answer 2

The easiest way to solve this problem is to start plugging in the values for y and x.

For "A" you have an x-value of 3 and a y-value of 1.  Plug these in and you get:

1 = (3) - 2.

Subtract.

1 = 1

Because this statement is true, "A" is a solution to the equation y = x - 2.

"A" is the answer.

If we were to try something else though, such as "B", we would end up with a false statement.

"B" has an x-value of 1 and a y-value of 3.

3 = (1) - 2

Subtract.

3 = -1

This statement is false, therefore, "B" is not a solution to the equation y = x - 2.