Question

Write an equation in point-slope form of the line through points (7,6) and (9, 2). Use (7,6) as the point (x1, y1).

Answer 1

Since the formula is y=mx+b, we can substitute the point (7,6) into it and get 6=6m+b. Substituting the other point, we get 2=9m+b.

Subtract the two equations from each other to find m, and we can get rid of b. The new equation is:

-3m = 4

m= -4/3

Plugging this into 6=6m+b,

6=6*(-4/3) +b

6= -8+b

b=14

Plugging the m and b values into the original formula,

y= -4/3x+14