Question

What is the equation of a line that passes through points (0, 4) and (-4, -8)? y = 2x + 4 y = 2x - 4 y = 3x + 4 y = 3x - 4

Answer 1

y= 3x +4

Explanation:

The equation of a line is usually written in the form of y=mx +c, where m is the gradient and c is the y-intercept.

To find the value of m, use the gradient formula below:

`gradient = (y1 - y2)/(x1 - x2)`

Gradient

`= (4 - ( - 8))/(0 - ( - 4)) \\ = (4 + 8)/(0 + 4) \\ = (12)/(4) \\ = 3`

Subst. m=3 into the equation.

y= 3x +c

To find the value of c, substitute a coordinate.

When x=0, y=4,

4= 3(0) +c

c=4

Thus, the equation of the line is y= 3x +4.