How do you find the y-intercept when you have the slope and a point?

How do you find the y-intercept when you have the slope and a point?
you use the equation y=mx+b; you use your point values to put in for x and y; slope is entered in for m and then you solve for b
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if you want to find the equation of a slope and point:
you use y-y*=m(x-x*)
the y* and x* are the numbers from your point
for example if you have the slope(m) 8/1 and the point (1,2)=(x*,y*)
then you would do the following-
1.........y - y* = m(x - x*)
2.........y - 2 = 8(x - 1)
3.........y - 2 = 8x - (-8)
4.........y - 2 = 8x + 8.........because eight x minus negative one equals eight x plus one
5.........y = 8x + 10.......because you add 2 to both sides of the equation
...........y = 8x + 10 is the equation answer
...........if you want to find the y-intercept from that:
6.........y-intercept equals (0,10)