F\left(x\right)=-5\left(x-10\right) ^2-8 whats is the vertex

t

step-by-step explanation:

ever thing time 1 is a multiply by 1 it get  

the anwser is x< -17/2

answer: $53750

steps:

list the principal and interest after the n-th year:

n       principal   simple interest

1     12500     375

2     25000     750

3     37500     1125

4     50000     1500

sum: $50000     $3750

total at end of year 4: $53750