SOLUTION: Please help! I don't even know where to start. divide (x^2-9y^2/7x^2-21y)/(x^2+3xy) Thanks!

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Please help! I don't even know where to start. divide (x^2-9y^2/7x^2-21y)/(x^2+3xy) Thanks!      Log On


   

Question 133358: Please help! I don't even know where to start.
divide (x^2-9y^2/7x^2-21y)/(x^2+3xy)
Thanks!
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
%28%28x%5E2-9%2Ay%5E2%29%2F%287%2Ax%5E2-21%2Ay%29%29%2F%28x%5E2%2B3%2Ax%2Ay%29 Start with the given expression



%28%28x%5E2-9%2Ay%5E2%29%2F%287%2Ax%5E2-21%2Ay%29%29%2A%281%2F%28x%5E2%2B3%2Ax%2Ay%29%29 Multiply the first fraction by the reciprocal of the second fraction



%28x%5E2-9%2Ay%5E2%29%2F%28%287%2Ax%5E2-21%2Ay%29%2A%28x%5E2%2B3%2Ax%2Ay%29%29 Combine the fractions


%28%28x%2B3y%29%28x-3y%29%29%2F%28%287%2Ax%5E2-21%2Ay%29%2A%28x%5E2%2B3%2Ax%2Ay%29%29 Factor x%5E2-9%2Ay%5E2 to get %28x%2B3y%29%28x-3y%29



%28%28x%2B3y%29%28x-3y%29%29%2F%287%28x%5E2-3y%29%2A%28x%5E2%2B3%2Ax%2Ay%29%29 Factor out the GCF 7 from 7%2Ax%5E2-21%2Ay


%28%28x%2B3y%29%28x-3y%29%29%2F%287x%28x%5E2-3y%29%2A%28x%2B3y%29%29 Factor out the GCF x from x%5E2%2B3%2Ax%2Ay


%28cross%28%28x%2B3y%29%29%28x-3y%29%29%2F%287x%28x%5E2-3y%29%2Across%28%28x%2B3y%29%29%29 Cancel like terms



%28x-3y%29%2F%287x%28x%5E2-3y%29%29 Simplify


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Answer:


So %28%28x%5E2-9%2Ay%5E2%29%2F%287%2Ax%5E2-21%2Ay%29%29%2F%28x%5E2%2B3%2Ax%2Ay%29 simplifies to %28x-3y%29%2F%287x%28x%5E2-3y%29%29