Question

I need help on this. Please

Answer 1

Answer: choice C, y = 0.014x+0.85

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Explanation:

Each column of the table represents an (x,y) pair of values

x = number of pages

y = cost

If we look at the first two columns, we see the two points (50,1.55) and (100,2.25). The x value is listed first. Let's compute the slope of the line through these two points

m = (y2-y1)/(x2-x1)

m = (2.25-1.55)/(100-50)

m = 0.7/50

m = 0.014

So far, we see the answer is between A,B or C as they have the slope of 0.014

Use this slope value, and one of the points -- say (x,y) = (50,1.55) -- to find the y intercept b

y = mx+b

y = 0.014x+b .... plug in the slope found earlier

1.55 = 0.014*50+b ... plug in the point (x,y) = (50,1.55)

1.55 = 0.7+b

1.55-0.7 = 0.7+b-0.7 ... subtract 0.7 from both sides

0.85 = b

b = 0.85

With m = 0.014 as the slope and b = 0.85 as the y intercept, we can say that y = mx+b turns into y = 0.014x+0.85. That narrows the answer down to choice C.