Answer:
vertex is a point where two sides meet
In a quadratic function, y = a(x²) the smaller the coefficient "a", the larger is the parabola:
From widest to narrowest:
1) y=1/3x² (Widest)
2) y= -1/2x² (Wider)
3) y=-9x² (narrowest)
The reason fractions need a common denominator before adding or subtracting is so that the numbers of pieces you are adding/subtracting are all the same size. Note that the numerator of a fraction just tells you how many pieces you have of that size.