You want to undo the (-9 1/2), so you will add 9 1/2 to each side
To convert to percent from fraction you divide the numerator by the denominator. from percent to decimal you move two decimal places to the left.
5x²+y²=3
by implicit differentiation we shall have:
10x+2yy'=0
the second derivative will be:
10+2y"=0
2y"=-10
y"=-5
I would say direct because the more gallons of gasoline used, the bigger the cost.
