4x^2 + 5xy - y^2 = 6
Implicitly differentiating both sides,
4(2x) + 5(x y' + y) - 2yy' = 0
where y' = dy/dx
8x + 5xy' +5y -2yy' = 0
combining y' terms
y' (5x-2y) +8x +5y = 0
y'(5x-2y) = -(8x+5y)
dy/dx = -(8x+5y)/(5x-2y)
or
dy/dx = (8x+5y)/(2y-5x)
He bought last year and year later total is $104.3
Each share he sold 62.80 with tax is 0.03
62.80x1.03= $64.684 for each share
So there are 40 shares
64.684 x 40= $2587.36
What are the numbers? I can't really see them.
