Let's simplify the expression step by step:
The expression is:
\[ -4.08 \div 1.2 - (-4.2) \times 1.5 \]
- Calculate \(-4.08 \div 1.2\):
\[ -4.08 \div 1.2 = -3.4 \]
- Calculate \((-4.2) \times 1.5\):
\[ -4.2 \times 1.5 = -6.3 \]
Since we have \(-(-4.2 \times 1.5)\), we take the opposite of \(-6.3\), which is \(6.3\).
- Now put it all together:
\[ -3.4 - (-6.3) = -3.4 + 6.3 \]
- Calculate \(-3.4 + 6.3\):
\[ -3.4 + 6.3 = 2.9 \]
Thus, the simplified expression is:
\[ \boxed{2.9} \]