Question

What is point slope form and how can it be used to find the equation of a line?

Answer 1

Point slope
\(y-y_1=m(x-x_1)\)


Where \((x_1,y_1)\) and slope = m

Answer 2

thanks!

Answer 3

For example, if you want to find an equation of the line passing by the points (1,1) et (3,-1) :
First, we can write
\[y=mx+b\]
where m is the slope which can been found by :
\[m=\frac{y_2-y_1}{x_2-x_1}=\frac{2-1}{-1-1}=-1.\]
Then, for finding b, we substitute with a point from the line, for example (1,1), so :
\[1=-1\times 1+b\]
and hence :
\[b=-2.\]
So the equation of the line is :
\[y=-x-2.\]

Answer 4

thanks @Noura11 that helped a lot!