Answer:
84
Step-by-step explanation:
Pretend her first 3 quizzes were all 83 since that was the average. So the 4th was 87.
83+83+83+87 = 336
Divide by the total number of quizzes because they are equally weighted.
336/4 = 84
Her new average score is 84.
16
i would try but not 100% sure
y" - 8y' + 15y = 0
2nd order Homogeneous DE.
Solving Quadratically
k² - 8k + 15 = 0
k= 5 or k= 3.
Two real and Unequal roots.
y= Ae^5x + Be^3x.