This is worth half of my grade

What does x = in this equation x+3+2x=x+5

Assume that the weights of quarters are normally distributed with a mean of 5.67 g and a standard deviation 0.070 g. a vending machine will only accept coins weighing between 5.48 g and 5.82 g. what percentage of legal quarters will be rejected? round your answer to two decimal places.

Given the two similar triangles, how do i find the missing length? if a=4, b=5, and b'=7.5 find a'