Use the chain rule.
Let u = 25sin²(x), such that dy/dx = dy/du · du/dx
1st answer - he'd pay $751
2nd answer -
(√3n)-23=16
Put all of the numbers without a variable on the right side of the equation
(√3n)=39
Simplify
<span>1.732051n</span>=<span>39
</span>
Divide 39 by 1.732051
n=<span>22.516658
Round
n=22.5</span>
1/9 or 11/100
Hope that helps