The old amount of iron was 1.2 mg per serving, and now the new amount of iron is 1.8 mg per serving, so to calculate the percent increase in iron, we just need to calculate the difference between the new value and the old value, and then divide the result by the old value:
The axis of symmetry divides the parabola into two equal parts. FRom point x=-4 to x=8, the difference is 12 units and the centre is6 units on each side. Using a number line, the axis of symmetry is at point x=2