Question

A student was asked to find the slope of the line through the points (4,8) and (-3,5). His answer, t/?f=-%5Cfrac%7B3%7D%7B7%7D" id="TexFormula1" title="-\frac{3}{7}" alt="-\frac{3}{7}" align="absmiddle" class="latex-formula">, was incorrect. He showed his work as $\frac{5-8}{4-(-3)}$=$-\frac{3}{7}$=$-\frac{3}{7}$.
What went wrong? Give the correct slope.

Answer 1

Answer:

$m=\frac{-3}{-7}$

Step-by-step explanation:

Given the following question:

Point A = (4, 8) = (x1, y1)
Point B = (-3, 5) = (x2, y2)

In order to find the slope any two points given we use the formula to find slope or rise/run.

$m=\frac{y2-y1}{x2-x1}$
$m=\frac{5-8}{-3-4} =\frac{-3}{-7}$
$m=\frac{-3}{-7}$

The reason why the students answer is incorrect because he substituted incorrectly. More specifically the run part of the formula for slope. The formula for slope goes x2 - x1 which means it should be -3 - 4, not -4 - 3, which will give you the answer -7.

Hope this helps.