#### Answer

$14ab+10a^{2}b-18a^{2}+12b^{2}$

#### Work Step by Step

We are given the expression $(14ab-10a^{2}b+6b^{2})-(18a^{2}-20a^{2}b-6b^{2})$. We can subtract the second polynomial from the first polynomial by adding the opposite of the second polynomial to the first polynomial.
$(14ab-10a^{2}b+6b^{2})+(-18a^{2}+20a^{2}b+6b^{2})$
We can combine like terms to simplify.
$14ab+(-10a^{2}b+20a^{2}b)-18a^{2}+(6b^{2}+6b^{2})=14ab+10a^{2}b-18a^{2}+12b^{2}$