Question

Suppose you are saving money for a new cell phone. At week 0 you have $20 and at week 10 you have $100. If y represents the amount of money you have saved and x represents the number of weeks, find and interpret the slope of the linear equation. A. 1/8 ; $8 is put away each week. B. 10; $10 is put away each week. C. 8; $8 is put away each week. D. 1/10; $10 is put away each week

Answer 1

you have 2 points (0,20) and (10,100) now find the slope using change in y divided by change in x
m=(100-20)/(10-0)
m=80/10
m=8 is the slope

Answer 2

If we plot the given values in the Cartesian plane, the points to which the line would pass are (0, 20) and (10, 100). Thus, the slope m is,
m = (y2 - y1) / (x2 - x1)
Substituting,
m = (100 - 20) / (10 - 0) = 8
Thus, I saved 8 pesos per week. The answer to the question is letter C.