These are all quadratic equations
![y = ax^(2) + bx + c](https://img.qammunity.org/2019/formulas/mathematics/middle-school/4pknqkz41l3jh9tk2cc97q6p7bhd5fiqol.png)
so you can use the formula
![R = b^(2) - 4ac](https://img.qammunity.org/2019/formulas/mathematics/middle-school/m5w933sgu1bzlpsnof3o3o0wdga79ot96q.png)
to determine the number of real answers.
If R < 0, there is 0 real solution.
If R = 0, there is 1 real solution.
If R > 0, there are 2 real solutions.
Let me do the first one :
![y = -3x^(2) + x + 12](https://img.qammunity.org/2019/formulas/mathematics/middle-school/neyg1q59t89pmy59zr9m8qabyk3p4rgfit.png)
You find
![R = 1^(2) - 4 * (-3) * 12 > 0](https://img.qammunity.org/2019/formulas/mathematics/middle-school/8ofld1sl8avbr9iiddbn93yu0s4mtuqc9l.png)
Thus this equation has two real solutions.