#### Answer

$6a^3-0.2a^2+7$

#### Work Step by Step

Since the expression in parenthesis is preceded by a negative sign, then all terms inside the parenthesis will alter its sign when the parenthesis is removed. Hence, the given expression, $
-(-6a^3+0.2a^2-7)
$, is equivalent to
\begin{array}{l}
6a^3-0.2a^2+7
.\end{array}