First question:
First of all, you have to rewrite the quadratic equation bringing everything to the left hand side, so you have
[tex] 3x^2 - x = 4 \iff 3x^2 - x - 4 = 0 [/tex]
Now, the coefficients of a quadratic equation are usually read as [tex] ax^2 + bx + c = 0 [/tex], i.e. [tex] a [/tex] is the coefficient of [tex] x^2 [/tex], [tex] b [/tex] is the coefficient of [tex] x [/tex] and [tex] c [/tex] is the constant term.
Once you rewrite your equation, the coefficient of [tex] x^2 [/tex] is 3, the coefficient of [tex] x [/tex] is [tex] -1 [/tex] and the constant term is [tex] -4 [/tex], so the correct answer is D.
Second question:
As discussed above, the first step for solving a quadratic equation is bringing everything to the left, so that you are in the form [tex] ax^2 + bx + c = 0 [/tex]. So, the first thing you have to do is to transform
[tex] x^2+x=12 \to x^2 + x - 12 = 0 [/tex]
