To find the x-intercepts of a function set f(x) (or y) to zero. If you think about it graphically, the x-intercepts occur when your graph hits the x-axis, and the x-axis is the line y=0.
Now the equation looks like this: 0 = -3x2+7x+12
and you can use quadratic formula to find the...

A stem and leaf plot is a way to organize data. Lets say for example you are measuring the yearly rainfall (in inches) in cities around the US.
One way to group the data is to just list all the measurements: 9 14 16 25 22 36 ...

Compound interest on a loan would qualify as a function, and it falls into the category of exponential functions
an example of this type of function is f(x) = ax for some constant a
If you think about the amount of money owed on...

= (x-4)(x-4) + (x-2)(x-2) + (x-3)(x-3)
= x2-4x -4x +16 + x2 -2x -2x +4 + x2-3x - 3x + 9
= x2 + x2 + x2-8x -4x -6x +16...