1) If the cost of a notebook is represented by 3x-1, express the cost of four notebooks

(Separate questions)

2) what must be added to 2x^2-6x-12 in order to get 7x^2-15

1) 12x-4

2) 5x^2+6x-3

Step-by-step explanation:

For number one, just multiply 3x-1 by for using the distributive property.

This would be 4 (3x-1) = 12x-4.

For the second question, you know that you need to add something to 2x^2-6x-12 in order to get 7x^2-15.

2x^2 + ? = 7x^2. The question mark would be 5x^2.

You can see that there is no x variable in 7x^2-15. That means you just need to take the opposite of - 6x, which is 6x.

Finally to go from - 12 to - 15, you need to subtract 3.

This will leave you with 5x^2+6x-3