Answer
$12x^2+11$
Work Step by Step
Use the distributive property to find:
$=18x^2+4-[6x^2-12+5]
\\=18x^2+4-(6x^2-7)
\\=18x^2+4-6x^2-(-7)
\\=18x^2+4-6x^2+7$
Rearrange and regroup the terms, and then simplify using the distributive property to find:
$=(18x^2-6x^2)+(4+7)
\\=(18-6)x^2+11
\\=12x^2+11$