Answer
$$-48$$
Work Step by Step
To simplify this expression, you want to follow order of operations according to PEMDAS, which states that you evaluate the following in order: parentheses, exponents and radicals, multiplication and division, and, finally, addition and subtraction.
In this problem, we have outer brackets and inner parentheses. We have to evaluate from the inner to the outer, so we evaluate what is in the inner parentheses first:
$$6[5 + 2(-5) - 3]$$
Now we evaluate what is within the brackets, but we need to do the multiplication first:
$$6[5 - 10 - 3]$$
Now we can evaluate what is inside the brackets from left to right because the only operations are addition and subtraction:
$$6[-5 - 3]$$
Subtract $3$ from $-5$:
$$6(-8)$$
Now we multiply:
$$-48$$
