A line passes through (3, 7) and (-4, 9). Find the value for x if (x, 1) is on the line.
step 1
find the slope of the line
m=(9-7)/(-4-3)
m=2/-7
m=-2/7
step 2
find the equation of the line in point slope form
y-y1=m(x-x1)
we have
m=-2/7
(x1,y1)=(3,7)
substitute
y-7=(-2/7)(x-3)
step 3
substitute the point (x,1)
1-7=(-2/7)(x-3)
-6=-(-2/7)(x-3
solve for x
multiply by -7 both sides
42=2(x-3)
divide by 2 both sides
21=x-3
x=21+3
x=24)
