I HOPE IT WILL HELP YOU. I DID HOW I KNOW .
3x - 12
3(3x/3 - 12/3)
3(x - 4)
The answer is: 3(x - 4).
Answer:


Step-by-step explanation:
<u>Errors in Algebraic Operations
</u>
It's usual that students make mistakes when misunderstanding the application of algebra's basic rules. Here we have two of them
- When we change the signs of all the terms of a polynomial, the expression must be preceded by a negative sign
- When multiplying negative and positive quantities, if the number of negatives is odd, the result is negative. If the number of negatives is even, the result is positive.
- Not to confuse product of fractions with the sum of fractions. Rules are quite different
The first expression is

Let's arrange into format:

We can clearly see in all of the factors in the expression the signs were changed correctly, but the result should have been preceeded with a negative sign, because it makes 3 (odd number) negatives, resulting in a negative expression. The correct form is

Now for the second expression

Let's arrange into format

It's a clear mistake because it was asssumed a product of fractions instead of a SUM of fractions. If the result was correct, then the expression should have been

It will travel 180 miles
4.5 • 40= 180
The total mass, in kilograms, of the nails the carpenter bought is 3.9 kilogram
<h3><u>Solution:</u></h3>
Given that carpenter bought 750 nails
Each nail has a mass of
kilogram
To find: total mass, in kilograms of the nails bought
The total mass of the nails bought can be found out by multiplying number of nails bought by mass of each nail
Number of nails bought = 750
Mass of each nail =
kilogram
total mass of the nails bought = number of nails bought x mass of each nail


Thus the total mass of nails bought is 3.9 kilogram