A=(2x+1)/B
C=(5x-14)/B
AC=(2x+1)/B * (5x-14)/B
AC=(10x² - 23x - 14)/BE
Answer:15
Step-by-step explanation:
Given
Craftsman sell 10 Jewelry set for $500 each
For each additional set he will decrease the price by $ 25
Suppose he sells n set over 10 set
Earning
Earning 

differentiate to get the maximum value

Equate
to get maximum value



Thus must sell 5 extra set to maximize its earnings.
C
the explanation is in the photo
Answer:
let length be l
breadth=l-10m
area of rectangular park=236m²
Step-by-step explanation:
area of rectangular park=236m²
l×(l-10)=236
l²-10l-236=0
l²-2.l.5+5²-236-5²=0
(l-5)²-236-25=0
(l-5)²=261
(l-5)=√261
(l-5)=16.15
l=16.15+5=21.15
b=l-10=21.15-10=11.15