Find the equation of a line given the point and slope below. Arrange your answer in the form y = mx + b, where b is the constant.

(0, 0)
m = 2
I need help understanding how to set up the equation.

Question

Find the equation of a line given the point and slope below. Arrange your answer in the form y = mx + b, where b is the constant.

(0, 0)
m = 2
I need help understanding how to set up the equation.

anonymous · Answer

The equation you want should look like this: $y=mx+b$.

You're told that $m=2$, so $y=2x+b$.

You know the line passes through the origin, (0,0). This means when $x=0$ you have $y=0$. Plug this into the equation above:
$$0=2(0)+b~~\Rightarrow~~b=0$$
So, the equation of the line is $y=2x$.

anonymous · Answer

Does that formula work for any variables? ex. (5,5) m = -3 ?

anonymous · Answer

Yes, the equation of a line depends on the slope and any known point on the line.

Given (5,5) and $m=-3$ (the point and slope respectively), you would have
$$5=-3(5)+b~~\Rightarrow~~b=20$$and$$y=-3x+20 $$

anonymous · Answer

Okay thank you very much!

anonymous · Answer

You're welcome