1. y = x - 1
- Input, x: 0; x - 1: 0 - 1; Output, y: -1; (x, y): (0, -1)
- Input, x: 1; x - 1: 1 - 1; Output, y: 0; (x, y): (1, 0)
- Input, x: 2; x - 1: 2 - 1; Output, y: 1; (x, y): (2, 1)
- Input, x: 3; x - 1: 3 - 1; Output, y: 2; (x, y): (3, 2)
2. y = 2x + 6
- Input, x: -2; 2x + 6: 2(-2) + 6; Output, y: 2; (x, y): (-2, 2)
- Input, x: -1; 2x + 6: 2(-1) + 6; Output, y: 4; (x, y): (-1, 4)
- Input, x: 0; 2x + 6: 2(0) + 6; Output, y: 6; (x, y): (0, 6)
- Input, x: 1; 2x + 6: 2(1) + 6; Output, y: 8; (x, y): (1, 8)
3. y = -2x + 2
- Input, x: -1; -2x + 2: -2(-1) + 2; Output, y: 4; (x, y): (-1, 4)
- Input, x: 0; -2x + 2: -2(0) + 2; Output, y: 2; (x, y): (0, 2)
- Input, x: 1; -2x + 2: -2(1) + 2; Output, y: 0; (x, y): (1, 0)
- Input, x: 2; -2x + 2: -2(2) + 2; Output, y: -2; (x, y): (2, -2)
4. y = 20x
- Input, x: 2; 20x: 20(2); Output, y: 40; (x, y): (2, 40)
- Input, x: 3; 20x: 20(3); Output, y: 60; (x, y): (3, 60)
5. Plot the points (0,0), (1,20), (2,40), and (3,60) on the graph and draw a straight line through them.
6. The relationship between x and y is linear.
7. The relationship is proportional because y is always 20 times x, which means y/x = 20 (a constant), and the graph passes through the origin (0,0).
Parent Tip: Review the logic above to help your child master the concept of describing functions worksheet.
