ACT Math : How to find the equation of a line

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #141 : Coordinate Geometry

Which line passes through the points (0, 6) and (4, 0)?

Possible Answers:

y = 1/5x + 3

y = 2/3 + 5

y = –3/2 – 3

y = 2/3x –6

y = –3/2x + 6

Correct answer:

y = –3/2x + 6

Explanation:

P1 (0, 6) and P2 (4, 0)

First, calculate the slope:  m = rise ÷ run = (y2 – y1)/(x– x1), so m = –3/2

Second, plug the slope and one point into the slope-intercept formula: 

y = mx + b, so 0 = –3/2(4) + b and b = 6

Thus, y = –3/2x + 6

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