Help needed.

7x^2+3y^2-4x

Choose the first option

Step-by-step explanation:

Ok, so let me show you how to do this.

First, distrubute the negative sign

12x^2-11y^2-13x-(5x^2-14y^2-9x)=

12x^2-11y^2-13x-5x^2+14y^2+9x

Now combine like terms

(12x^2-5x^2)=7x^2

(-11y^2+14y^2)=3y^2

(-13x+9x)=-4x

7x^2+3y^2-4x is the answer.

a_n = a_1 + (n - 1)d

the first term is 6.

the common difference d = ?

when you find d, replace n with 7 and d with the common difference to find your answer.