Question

What is the equation of this line in slope-intercept form

Answer 1

• (1,-3)
• (-1,5)

Slope=

• m=5+3/-1-1
• m=8/-2
• m=-4

Equation in point slope form

• y+3=-4(x-1)
• y+3=-4x+4
• y=-4x+1

Answer 2

`y=-4x+1`

Explanation:

We have been given two points on the line, so:

`\textsf{let}\:(x_1,y_1)=(-1,5)`

`\textsf{let}\:(x_2,y_2)=(1,-3)`

Calculate the slope using the slope formula:

`\textsf{slope}\:(m)=(y_2-y_1)/(x_2-x_1)=(-3-5)/(1-(-1))=-4`

From inspection of the graph, it appears that the y-intercept (where the line crosses the y-axis) is at (0, 1). However, just to be sure, use the point-slope form of linear equation.

Point-slope form of linear equation:
`y-y_1=m(x-x_1)`

(where m is the slope and (x₁, y₁) is a point on the line)

`\implies y-5=-4(x-(-1))`

`\implies y-5=-4x-4`

`\implies y=-4x+1`

Therefore, the equation of the line in slope-intercept form is:

`y=-4+1`