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Question 174857: A quiz question concerning finding an equation of a parallel line containing the points (2,-1) and parallel to the line 9x-3y=5. I found the slope of both lines to be -3. But their answer (which is y=-3x - 7) confused me. How did they arrive at -7? I used the Point-Slope Equation & Slope Intercept Equation. For example, using the point-slope equation: (y-y1)= m(x-x1)=(y-(-1)) = -3(x - 2). I cannot find how this results in a -7 (or y= -3x - 7) when you do the calculation. Please show me how. Thanks, Charlie
Answer by actuary(112)   (Show Source):
You can put this solution on YOUR website! The equation for the given line is 9x-3y=5. Rewriting this in standard form we have -3y=-9x+5 or
y =3x-5/3 so the slope is 3
For the line to be determined, using the point slope formula, we have
y-(-1))=3*(x-2)
This can be simplified to y-(-1)+(-1)) = 3x-6+(-1)
So the equation is y=3x-7
I hope that this helps
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