SOLUTION: Adding rational # Cant figure this problem out..Any help will be appreciated. 5 1 _____ + _______ 7x+35 42x+126 I tried factoring both Denominator 7(x+5) 42

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Adding rational # Cant figure this problem out..Any help will be appreciated. 5 1 _____ + _______ 7x+35 42x+126 I tried factoring both Denominator 7(x+5) 42      Log On


   

Question 35317: Adding rational #
Cant figure this problem out..Any help will be appreciated.
5 1
_____ + _______
7x+35 42x+126

I tried factoring both Denominator
7(x+5) 42(x+3)
then 7(42)=294(x+5)(x+3)
I am lost after that
Answer by rapaljer(4671) About Me  (Show Source):
You can put this solution on YOUR website!
5%2F%287%28x%2B5%29%29+%2B1%2F%2842%28x%2B3%29%29+

Your problem was that you did not find the Lowest Common Denominator. Notice that 7 divides evenly into 42, so the LCD = 42%28x%2B5%29%28x%2B3%29+

Now, multiply the first fraction by 6(x+3) and the second fraction by (x+5):



Now, the LCD is 42(x+3)(x+5), and that becomes the denominator of the fraction. The numerator of the fraction becomes the sum of the numerators.
+%2830%28x%2B3%29+%2B+%28x%2B5%29+%29+%2F%2842%28x%2B3%29%28x%2B5%29%29+

NOW DON'T DIVIDE ANY OF THESE OUT!! They look like factors, but they are NOT factors!! Multiply out the numerators.
+%2830%28x%2B3%29+%2B+%28x%2B5%29+%29+%2F%2842%28x%2B3%29%28x%2B5%29%29+
+%2830x%2B90+%2B+x%2B5%29%2F%2842%28x%2B3%29%28x%2B5%29%29+
+%2831x%2B95+%29%2F%2842%28x%2B3%29%28x%2B5%29%29+

R^2 at SCC