Answer:
The question doesn't make sense without more explaining are you sure this is all right?
Step-by-step explanation:
69.9 is exactly 3 standard deviations away, which means that 78.9 is +3 (more than 3) standard deviations
So the answer is 78.9
times by a on both sides
a(a+8)= -5
expand brackets
a^2 + 8a = -5
minus 5 on both sides to set equal to 0
a^2 + 8a -5 = 0
use quadratic formula to get 2 solutions
-
type into calculator. one solution from + other from -