3 6 9 7 8 9 10 3 6 9 7 8 9 10

constant straight line origin constant *The word constant means at the same rate of change. straight line origin *The word origin means at point at (0,0). constant

 ($25)(0) 0  ($25)(1) 25  ($25)(2) 50  ($25)(3) 75  ($25)(4) 100  A straight monthly fee is sometimes referred to as a flat rate (no change)  ($25)(0) 0  ($25)(1) 25  ($25)(2) 50  ($25)(3) 75  ($25)(4) 100  ($25)(5) y (input value) (output value)  The slope is $25 ($25 per month)  The slope (rise / run) is 25/1.  YES. The table is proportional, as the rate of change each month is constant / not changing. YES. All points lie in a straight line. AND The line passes through or begins at the origin (0,0).

y = 25x The slope is 25. It is the coefficient in front of x. They have a constant rate and pass through (0,0) with in a straight line. y = mx slope x represents (input value) and y represents (output value)

y = 1.38x y=cost and x=pounds (apples) The slope is 5.52/4 or $1.38 per pound The rise/run is 4/3. YES. $1.38 per pound is constant. Also, zero pound = zero cost. YES. Slope is constant. Also, line passes through origin (0,0). y = 1.38x y=cost and x=pounds (apples) y = 4/3x

Origin Will not pass through (0,0). not constant Origin Will not pass through (0,0). y-intercept y-intercept: Ordered pair (0, y) x must be zero when finding the y-intercept

20(0) + 10 10 20(1) + 10 30 20(2) + 10 50 20(3) + 10 70 20(4) + 10 90 20(x) + 10 y Slope is 20. Slope is 20/1. y-intercept is 10, point at (0,10) y-intercept is 10, point at (0,10) No. ratio between x and y is not constant. Line does not pass through the origin (0,0).

y = 20x + 10 The slope is the coefficient in front of x. The slope is 20. The y-intercept is the number after x. The y-intercept is 10. They have a y-intercept is not (0,0). y = mx + b slope y-intercept

Line would begin at (0,12). Non-proportional. -4 9 no ¾ -8 no 1.25 yes y = 12 + 0.75x 0.75 12 Line would begin at (0,12). Non-proportional.