Please help me solve these Qs. Thank you!!

1)

Consider the following function. R(x) = -2x2 + 16x - 22 (a) Use the quadratic formula to find the zeros of f. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.) X (b) Find the maximum or minimum value of R(x). R(x) = (c) Sketch the graph of f. y 200 200 180- 100- -15 -10 -5 10 15 X -15 -10 -5 5 10 X 15 - 100 -100- -2001 -2001 y 200 2001 100 100- -15 10 -5 5 X 10 15 -15 -10 -5 5 10 X 15 -100- -100 -200F -2001When a certain drug is taken orally, the concentration of the drug in the patient's bloodstream after & minutes is given by C (t), where 0 S & $ 240 and the concentration is measured in mg/L. C(t) = 0.09r - 0.0005t 2 (a) When is the maximum serum concentration reached. minutes (b) What is that maximum concentration? Give an exact answer or one correct to the nearest tenth. mg/L