Question

Question 19 (03.06 LC)

Choose the equation below that represents the line passing through the point (1, -4) with a slope of 1/2. (1 point)
y - 4 = 1/2(x +1)
y + 4 = 2(x - 1)
y + 4 = 1/2(x - 1)
y - 4 = 2(x + 1)

Answer 1

Answer: y + 4 = 1/2(x - 1)

Explanation:

The form of a straight line quation is y=mx+b, where m is the slope [(1/2) in this case] and b is the y-intercept (the value of y when x=0). We can already eliminate two of the options (2nd and 4th) since those slopes are 2.

To decide between y - 4 = 1/2(x +1) and y + 4 = 1/2(x - 1), we can see which equation is true for the point (1,-4):

Does y - 4 = 1/2(x +1) work for (1,-4)? [i.e., will y = -4 when x=1?]

y-4 = 1/2(1+1)?

y = 5 NO

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Does y + 4 = 1/2(x - 1) work for (1,-4)? [i.e., will y = -4 when x=1?]

y+4 = 1/2(1-1)

y = -4 YES

The equation is y + 4 = 1/2(x - 1)