Hi, i'm using an online evaluation tool, and it's not excepting my answer. There are 2 reasons for this.

1) My answer input is wrong

2) The machine is wrong

Now i've done the question 3 or 4 times now with differing answers only in + & - signs, but input all answers into the tool and it always comes back as wrong.

This is the question

differentiate $\displaystyle \frac{3x+2}{7x^2+9x+8}$

i'm using the quotient rule as i know it which is

$\displaystyle \frac{(v.u')-(u.v')}{v^2}$

and i get this as my answer

$\displaystyle \frac{-21x^2-28x+6}{49x^4+126x^3+193x^2+144x+64}$

So am i right, or am i wrong?