Question

A student finds the slope of the line between (8, 17) and (1, 4). She write 17-4/1-8. What mistake did she make?

Answer 1

Answer: OPTION D.

Step-by-step explanation:

The formula that is used to calculate the slope of a line is:

$m=\frac{y_2-y_1}{x_2-x_1}$

Where $(x_1,y_1)$ and $(x_2,y_2)$ are two points on the line.

In this case the student finds the slope of the line that passes trough these points:

$(8, 17)\\(1, 4)$

You can notice that she writes in the numerator that:

$y_2=17\\y_1=4$

So she chose the point $(1, 4)$ as $(x_1,y_1)$  and the point $(8, 17)$ as $(x_2,y_2)$.

Then $x_2$ and $x_1$ in the denominator must be:

$x_2=8\\x_1=1$

Therefore, she did not keep the order of the points the same in the numerator and the denominator.