The equation of a circle is:

Where (xc,yc) are the coordinates of the center.
Center (5, -5)
Radius = 3
(x-5)²+(y+5)²=3²
x²-10x+25+y²+10y+25=9
x²+y²-10x+10y+41=0
Answer:
55%
the percent decrease of the sale price from the regular price is 55%
Step-by-step explanation:
Percentage decrease is the percentage change in the sales price (regular and new)
Percentage decrease %∆P = ∆P/Pr × 100%
∆P = change in sales price = $135 - $60.75
Pr = regular price = $135
Substituting the values;
%∆P = (135-60.75)/135 × 100%
%∆P = 55%
the percent decrease of the sale price from the regular price is 55%
Whats the rest of the problem?
If you're just starting calculus, perhaps you're asking about using the definition of the derivative to differentiate
.
We have

Expand the numerator using the binomial theorem, then simplify and compute the limit.

In general, the derivative of a power function
is
. (This is the aptly-named "power rule" for differentiation.)