You are going to purchase a new iPhone for $479.99 and you have 2 coupons but can only use one. The first coupon is $100 off the original price. The other coupons is 20% off the original price. Which coupon is the better discount and by how much?

Astudent draws two parabolas on graph paper. both parabolas cross the x-axis at (–4, 0) and (6, 0). the y-intercept of the first parabola is (0, –12). the y-intercept of the second parabola is (0, –24). what is the positive difference between the a values for the two functions that describe the parabolas? write your answer as a decimal rounded to the nearest tenth