What two positive real numbers whose product is 21 have the smallest possible sum?

Step-by-step explanation:

Let x  and y are the two positive real numbers

product of two numbers is 21

The sum of the two numbers is f(x) =x+y

Replace y with 21/x

we need to find smallest possible sum , so we take derivative using power rule

when sum is minimum then the derivative is equal to 0

multiply both sides by x^2

Take square root on both sides

y-1700=200(x+4)

step-by-step explanation:

200(x+4) is 200x + 800 she is saving 200 per week x is the weeks and the -1700 is. us that’s howmuch she already had