Answer:
y = 3x - 10
Explanation:
The slope-intercept form is y = mx + b, where m is the slope and b is the y-intercept (the value of y when x is zero).
See the attached worksheet. Let's calculate slope, m. Slope is defined as the Rise/Run, or change in y over the change in x. Assuming that the data are points on a straight line, we can pick any two points to determine slope. Let's use (25,65) and (28,74). See the worksheet. The slope,m, is shown to be 3. Now we can write:
y = 3x + b
To find b, the y-intercept, we can use the above expression and substitue any of the given points for x and y, leaving b as the only unknown. Let's use point (25.65):
y = 3x + b
65 = 3*(25) + b [for point (25,65)]
65 = 75 + b
b = - 10
The equation is therefore y = 3x - 10