Question

What is the equation of the line that passes through the point (-3, -8) and has a
slope of 4?

Answer 1

y = 4x + 4

Explanation:

The equation of a line is most commonly given in the slope-intercept form.

Slope-Intercept Form

Slope-intercept form is given by the formula y=mx+b, where m is the slope and b is the y-intercept. This form is most commonly used because it is easy to draw a graph from and it is very concise. We already know one of the constants, m = 4. So, to find the equation we need to solve for b.

Solving For b

To solve for b, we need to plug in all of the information that we are given into the formula. We are given 3 pieces of info for this point: y = -8, x = -3, m = 4.

• -8 = -3(4) + b

Then, multiply.

• -8 = -12 + b

Finally, add 12 to both sides.

• 4 = b

Now that we know the value of b, we can go back to the formula and plug in both constants, y = 4x + 4.