Adding Rational Expressions

Question

$$\frac{7a}{6a^2-15a} + \frac{12a}{4a^2-25}$$

I determined the LCD of the denominators: $(3a)(2a-5)(2a+5)$. I then multiplied all nominators by the LCM, combined the terms and got:

$$\frac{a(86a+95)}{(3a)(2a-5)(2a+5)}$$

Where did I go wrong?

Answer 1

$$\frac{7a}{6a^2-15a} + \frac{12a}{4a^2-25} = \frac{7}{3(2a-5)} + \frac{12a}{(2a-5)(2a+5)} = \frac{7(2a+5) + 12a3}{3(2a-5)(2a+5)} = \frac{50a+35}{3(2a-5)(2a+5)} = \frac{5(10a+7)}{3(2a-5)(2a+5)}$$