I'm sending you two screenshots of the explanation I hope this helps.
Answer:
y = 3x - 5
Step-by-step explanation:
We know that the equation 'y = 3x + ?' intersects the point (1, -2). This means that when x = 1, y = -2 in out equation above. To solve this just plug in the x and y values to get '?'.

Now that we know '?' is -5, we write it back into slope intercept form, so our final answer is y = 3x - 5
Answer:
To make it trinomial it has to be ax²+bx+c
The first one is correct.