find the quotient

6x^3-5x^2-13x+13/2x+3

If the numerator can be factorized, it would be relatively easy to cancel common factors, if there are any.

In this case, the numerator cannot be factorized into rational factors, so a long division is required.

The result is
3x²-7x+4 + 1/(2x+3)

If you have difficulty doing the long division, it is basically similar to long division of numbers by hand, with some minor modifications.

It is impossible to show long division without the capacity to format numbers here. You can read up at links such as:
http://www.purplemath.com/modules/polydiv2.htm
http://www.sosmath.com/algebra/factor/fac01/fac01.html
or some YouTube videos.