Question

Is the point (20,15) on the line? How do you know?

Answer 1

1. (4, 3) and (8, 6)

2. Yes. The line shows a direct proportion. y = 0.75x

Try (20, 15) in the equation.

15 = 0.75(20)

15 = 15

Point (20, 15) works in the equation, so point (20, 15) is on the line.

3.

Let x = 100.

y = 0.75x

y = 0.75 × 100

y = 75

Since x = 100 gives y = 75, point (100, 75) is on the line.

4.

Let x = 90

y = 0.75x

y = 0.75 × 90

y = 67.5

For x = 90, y must be 67.5. Since this point is (90, 68), it is not on the line.