(75 points). how do you solve quadratic-quadratic systems? describe the steps of how to do it with an example. i can't find any real information on how to solve them. (below is an example of what i need to solve to pass my test).

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.