find the y-intercept of a line that passes through (2,1) and has a slope of -5.

Question

i forgot what equation i have to use to find this out. can someone give me which equation i have to use?

or all the equations that deal with slopes please

Answer 1

A line of slope m passing through the point P1(x1,y1) has the equation:
(y-y1)=m(x-x1)
Post your answer if you need a check.
But you can check your own answer by substituting (x1,y1) in the equation to see if the two sides balance.

Answer 2

Oh yes, the y-intercept can be found by setting x=0 in the resulting equation of the line.
If you simplify the equation of the line using x=0, you should get:
y-intercept = y1-mx1