Question

The expression -3m - [2m + (5 - m)] + 7 was simplified as 2 - 4m. Without simplifying, explain how you can show that it has been simplified correctly.

Answer 1

(3n - 2m)^2 \\ \\ (3n)^2 - 2 \times 3n \times 2m + (2m)^2 \\ \\ 3^2n^2 - 2 \times 3n \times 2m + (2m)^2 \\ \\ 9n^2 - 2 \times 3n \times 2m + (2m)^2 \\ \\ 9n^2 - 2 \times 3n \times 2m + 2^2m^2 \\ \\ 9n^2 - 2 \times 3n \times 2m + 4m^2 \\ \\ 9n^2 - 12mn + 4m^2

The final result would be, 9n² - 12mn + 4m².

Answer 2

Answer: It is correctly simplified form.

Step-by-step explanation:

Since we have given that

$-3m-[2x+(5-m)]+7$

We need to simplify the above expression:

$-3m-2m-5+m+7\\\\=-5m+m+2(\text{gather the like terms})\\\\=-4m+2\\\\=2-4m$

So, $-3m-[2x+(5-m)]+7=2-4m$

Hence, it is correctly simplified form.