The line L passes through the points (-2,3) and (6,9). How do I find the equation of the line that is parallel to L and passes through the point (5,-1)?
- Find the gradient of line L. The gradient can be defined as the "change in y" divided by the "change in x". For this situation, the "change in y" would be 9 - 3 = 6. The "change in x" would be 6 - (-2) = 8. So the gradient of line L is 6/8 = 3/4 (=0.75) 2) Substitute the values you know into the equation y = mx + c. We already know that the line passes through (5,-1), so x = 5 and y = -1. Since the line is PARALLEL to line L, it will have the same gradient i.e. m = 0.75. Solve to find the value of c: -1 = (0.75 x 5) + c c = -1 - (0.75 x 5) = -4.75 3) Put all the pieces together, and you should have y = 0.75x - 4.75. You may be asked to convert the decimals into fractions, or express the equation in the form ax + by = c where a, b and c are integers.
JC
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