How do you use substitution to integrate 5x+103x2+12x7?

1 Answer
Sep 6, 2015

Start by factoring the 5 out of the numerator.

Explanation:

5x+103x2+12x7dx=5x+23x2+12x7dx

Now the derivative of the denominator is 6 times the numerator, so do a substitution to get a natural logarithm.

Let u=3x2+12x7 which makes du=(6x+12)dx

So our integral becomes: 561udu=56ln|u|+C.

And reversing the substitution gets us

5x+103x2+12x7dx=56ln3x2+12x7+C