Question

What is the equation of the line that has a slope of 3 and passes through the point (1, -2)?

y = 3x + 5
y = 3x − 5
y = 3x + 1
None of these choices are correct.

Answer 1

Hey there! I'm happy to help!

All of these answer options are in slope intercept form (y=mx+b) where m is the slope and b is the y-intercept.

If our slope is 3, our m will be 3 in the equation, which matches our answer options.

We now want to find the y-intercept (b). To do this, we plug in the point (1,-2) into the equation with our slope of 3 and then solve for b.

-2=3(1)+b

We flip the equation so b is on the left.

3(1)+b=-2

3+b=-2

We subtract 3 from both sides.

b=-5

So, the equation of this line is y=3x-5.

Have a wonderful day! :D

Answer 2

y = 3x-5

Explanation:

The slope intercept form of an equation is

y = mx+b where m is the slope and b is the y intercept

y = 3x +b

Substitute the point into the equation

-2 = 3(1)+b

-2 = 3+b

Subtract 3 from each side

-5 = b

y = 3x-5