Simplify the expression means solve a math expression and try to write it in the simplest way possible.
Distributive property:
[tex]a(b+c)=ab+ac[/tex]
For the given expression:
[tex]\begin{gathered} -6(-x-9)=(-6)(-x)+(-6)(-9) \\ \\ =6x+54 \end{gathered}[/tex]Then, the given expression simplified is 6x+54
