Question

Find the value of x so that the line passing through (10, 5) and (x, 9) has a slope of -2. -2 8 -8 2

Answer 1

The slope formula is the difference of the y values over the difference in the x values.  We have a slope, so we will fill in the formula with what we have and then solve for x: $-2= \frac{9-5}{x-10}$.  Multiply both sides by x-10 to get rid of the fraction.  -2(x-10) = 4.  Distribute to get -2x+20=4 and -2x = -16.  That gives us an x value of 8.