Camila is trying to find the equation of a line that passes through points (-1,16) and (5,88).does the equation y=12x+28 work?

Question

Camila is trying to find the equation of a line that passes through points (-1,16) and (5,88).does the equation y=12x+28 work?

Answer 1

Marlene is absolutely correct in how she worked

out the equation of the line.  Another way to do

this problem as stated is simply to plug the given

values of (x,Y) from the two points into the

equation y = 12x + 28 and see if they work

 

x=-1:  y = 12(-1) + 28 = 16  (-1,16) is on the line

 

x=5:   y = 12(5) + 28 = 88   (5,88) is on the line

 

Both points are on the line and the equation works

Answer 2

To solve this problem we should use the point-slope form of an equation of a line

y-y₁ = m(x-x₁), where (x₁,y₁) is one of the points given and m is the slope.

 

The formula for calculating a slope is

        y₂-y_{1          16-88          -72}

m = -------- = -------- = ------- = 12

        x₂-x_{1          -1-5             -6}

 

The equation of the line is

y-88 = 12(x-5)

y-88 = 12x-60

y = 12x + 28

 

Your equation is correct.