Question

What is the equation of a line that contains point (-2,8) and has a slope of 2?

Answer 1

the form of the linear equation is

`y=mx+b`

m is the slope of the line

b is the y-intercept

Since the slope of the line is 2

m = 2

Substitute it in the form above

`y=2x+b`

To find b substitute x and y in the equation by the coordinates of a point on the line

Since the line contains point (-2, 8), then

x = -2 and y = 8

`\begin{gathered} 8=2(-2)+b \\ 8=-4+b \end{gathered}`

Add 4 to both sides to find b

`\begin{gathered} 8+4=-4+4+b \\ 12=b \end{gathered}`

Substitute the value of b in the equation

`y=2x+12`

The equation of the line is y = 2x + 12