Find y if the slope between (8,y) and (14,-4) is -1/3

Answer 1

Slope is equal to the change in y divided by the change in x The change in x is 8 - 14 which is -6. The change in y is trickier because we don't have a number for one of the values, but that's OK, we can just use y, so it will be y - -4 or y + 4 so the change in y divided by the change in x is:

And that equals -1/3 so:

We solve these type of problems using cross multiplication.

-6 * -1 = 6 and 3 * (y + 4) = 3y + 12

so we can say the 6 = 3y + 12 now we can subtract 12 from both sides to get -6 = 3y and finally, divide both sides by 3 to get y = -2

Answer 2

(y - (-4)) / (8 - 14) = -1 / 3

3(y + 4) = -1(8 - 14)

3y + 12 = 6

3y = -6

y = -2