Ineed a break down on how to do my home work step by step. ex. ()+(-7)(3)

Let's break this problem down and solve it step-by-step.

STEP-BY-STEP SOLUTION:

Keep in mind the following:

Two positives together or two negatives together = positive

One positive and one negative together = negative

Okay, now let's begin solving the problem.

= ( 8 ) ( - 5 ) + ( - 7 ) ( 3 )

First we will multiply the brackets together.

= ( - 40 ) + ( - 21 )

Next we will remove the brackets and change the positive ( + ) and negative ( - ) symbol into just a negative symbol, as a positive and negative always equals a negative as stated previously.

= - 40 - 21

Now we will simply subtract 21 from - 40 to achieve our final answer.

= - 61

Hope this helps! :)
Have a lovely day! <3

The density of the cube is 40