Question

Given a line with slope of -1 and y-intercept of 8, which of the ordered pairs given below would NOT be on the line?

Answer 1

We have a line with slope -1 and y-intercept of 8.

We can write the equation of this line as:

$\begin{gathered} y=mx+b \\ y=-x+8 \end{gathered}$

Then, we can test the values for each x-coordinate and see if it matches the y-coordinate indicated by the point:

Point (3,5)

$y(3)=-3+8=5\longrightarrow\text{ is on the line}$

Point (2,10)

$y(2)=-2+8=6\ne10\longrightarrow\text{ is NOT on the line}$

Answer: the point (2,10) is not on the line.