A quadratic equation is a non-linear relationship between x and y.
For the secod part of your equation where you wonder is it meant to solve for 0, that's isn't always the case.
The reason sometimes a quadratic equation will be equal to 0, is when you are looking for the x-intercepts of your parabola. The reason why it's equal to 0 when you look for the x-intercepts is because the x-intercepts are always on the x-axis. Any point on the x-axis has a y-value of 0. This is why when we look for the x-interecepts, the y value is set to 0. We are solving for x when y = 0.
Wow! Thanks! I have another question (sorryy):
In the picture above, is the blue line the parabola?
(btw i found this on the web so I’m not sure if this is correct at all ;-;)
yes!! the blue line is a parabola!
a parabola is just a line that curves exactly in the way that you see it in the image that you posted =)
It might benefit you to learn about the quadratic equation as well. It is (-b +- √b^2 - 4ac)/(2a). It is commonly used to solve quadratic equations of form ax^2 + bx + c. There are also many other ways to solve, such as completing the square. I'd recommend learning about them, they are very interesting!