Please explain how to solve this equation! 15/a+x=b/a

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

Put the equation in slope intercept form by solving for y

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.