#### Answer

12$x^{2}$ + 11

#### Work Step by Step

18$x^{2}$ + 4 - [6($x^{2}$ - 2) + 5]
Step 1: Drop parentheses and multiply 6 with each term and change the sign of each term in parentheses: 6$x^{2}$ - 12
Step 2 Simplify inside brackets: -12+5 = -7
18$x^{2}$ + 4 - [6$x^{2}$ - 7]
Step 3 drop brackets and change the sign of each term in brackets
18$x^{2}$ + 4 - 6$x^{2}$ +7
Step 4: Group like terms (18$x^{2}$ - 6$x^{2}$) +(4+7)
Step 6: Combine the like terms
( 18$x^{2}$ - 6$x^{2}$) = 12$x^{2}$
So, final solution 12$x^{2}$ + 11