Question

A line passes through the point (-8,-7) and has a slope of 3. Write an equation for the line

Answer 1

Answer

y = 3x + 17

Explanation

If you you want to find the equation of a line you require a point on that line and is gradient.

gradient = 3

a point on the line is (-8, -7)

Chose another general point (x, y)

gradient = (change in y)/(change in x)

3 = (y- -7)/(x- -8)

3 = (y+7)/(x+8)

3(x+8) = y+7

3x+24 = y+7

y = 3x + 24 - 7

y = 3x + 17

Answer 2

Your answer is y = 3x + 24.

We already know that the first part of the equation is 3x, as the slope has been given to us. This means all we have to figure or is the y-intercept, which we can do by substituting in the coordinates we were given:

y = 3x + c
-7 = (3 × -8) + c
-7 = -24 + c
+ 24
17 = c

This gives us our y-intercept as 17, so then the final answer is y = 3x + 17.

I hope this helps!