It's a math problem subtracting unlikely fractions 14 / 2 - 9 / 8

What adds to be the bottom number but also multiplies to be the top number with 8 on the bottom and 15 on top

How do i i solve this equation? -18 = x/3 + 3

Asensitive measuring device is calibrated so that errors in the measurements it provides are normally distributed with mean 0 and variance 2.00. find the probability that a given error will be between -3 and 3.