Simplify each expression.

$77.\text{6}\left(2x+3y-1\right)$

In an expression, when a constant term is multiplied with term containing variables, then multiply the constant part of term and variable remain as it is.

In any expression or equation, the variable is an unknown quantity. It may be any alphabet or any special symbol.

In the expression, $6\left(4p\right)$, the constant term 6 is to multiplied with $4p$, so multiplied 4 and 6 and p remains as it is. The result obtained is $6\left(4p\right)=24p$.

Consider the provided expression.

$6\left(2x+3y-1\right)$

Multiply 6 with the terms inside the bracket. Recall that negative sign when multiplied with positive results in negative sign.

$\begin{array}{l}6(2x+3y-1)=6\left(2x\right)+6\left(3y\right)+6(-1)\\ =12x+18y-6\end{array}$

This cannot be further simplified.

Hence, the simplified form of the expression $6\left(2x+3y-1\right)$ is $12x+18y-6$