Here e is the base of the natural logarithm rounded to 2.718281828.
From x2 − 3y +7xy = 8y5, obtain:
x2 − (eln 3)y + 7xy = 8y5.
Then implicit differentiation gives
2x(dx/dx) − [ln 3 • eyln 3 • dy/dx] + d(7x)/dx • y + 7x • dy/dx = 5 • 8y4(dy/dx).
Rewrite as 2x − ln 3(eyln 3) y' + 7y + 7xy' = 40y4y'.
Express as 2x + 7y = 40y4y' + ln 3(eyln 3) y' − 7xy'.
Finally isolate y' as [2x + 7y] ÷ [40y4 + ln 3(eyln 3) − 7x].