[tex]\text{Simplify the expression}\\\\(-0.75x-7)-(6.5x+5.4)\\\\\text{Distribute the negative}\\\\-0.75x-7-6.5x-5.4\\\\\text{Combine like terms}\\\\-7.25x-7-5.4\\\\\boxed{-7.25x-12.40}[/tex]