Question

Which of the following represents the slope and y-intercept of the line on which the points lie?

m = 0.4; y-intercept = –1

m = 0.4; y-intercept = –3.4

m = 0.4; y-intercept = -3

m = 2.5; y-intercept = –3.4

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Answer 1

Second option: m = 0.4; y-intercept = -3.4

Explanation:

First we can write the model of a linear function:

y = mx + b

Then, to find the parameters m (slope) and b (y-intercept), we can use two of the points given:

x = 1 and y = -3:

-3 = m + b (eq1)

x = 6 and y = -1:

-1 = 6m + b (eq2)

Making (eq2) - (eq1), we have:

5m = 2

m = 0.4

Now finding b:

-3 = 0.4 + b

b = -3.4

So the correct answer is the second option: m = 0.4; y-intercept = -3.4