Cadence F.
asked • 01/07/22The point (-7,r) and (9,2) lie on a line with slope -3/2. Find the missing coordinate r.
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1 Expert Answer
Colleen S. answered • 01/09/22
Tutor
New to Wyzant
High School Algebra Teacher/Tutor
Hi Cadence! Let's begin by writing the point-slope form of the equation using the point (9, 2) and the slope -3/2. We get y - 2 = -3/2 (x - 9). Since this equation must be true for ANY point on the line, let's substitute the point (-7, r). This means that y = r and x = -7. We get r - 2 = -3/2 (-7 - 9). We can simplify this equation and start solving for r. We get r - 2 = -3/2 (-16). Then r - 2 = 24. Finally, r = 26. So the point (-7, 26) will be on the line, and r = 26.
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Colleen S.
Hi Cadence! Let's begin by writing the point-slope form of the equation using the point (9, 2) and the slope -3/2. We get y - 2 = -3/2 (x - 9). Since this equation must be true for ANY point on the line, let's substitute the point (-7, r). This means that y = r and x = -7. We get r - 2 = -3/2 (-7 - 9). We can simplify this equation and start solving for r. We get r - 2 = -3/2 (-16). Then r - 2 = 24. Finally, r = 26. So the point (-7, 26) will be on the line, and r = 26.01/09/22