Question

Determine which line the point (2, -1) lies on. y = 2x + 1 y = x + 5 y = 2x - 5 y = x - 2

Answer 1

To determine which line the point lies on, you can just plug in one of the numbers into the equations to see if it equals out.

(2, -1)  I will use the 2 and plug it in for x in the equation.

y = 2x + 1

y = 2(2) + 1

y = 5            The point does not lie on this line because when x = 2, y = 5  (2, 5)

y = x + 5

y = 2 + 5

y = 7          The point does not lie on this line because when x = 2, y = 7  (2, 7)

y = 2x - 5

y = 2(2) - 5

y = 4 - 5

y = -1           The point does lie on this line because when x = 2, y = -1  (2, -1)

y = x - 2

y = 2 - 2

y = 0      The point does not lie on this line because when x = 2, y = 0  (2, 0)