1.x^2+y^2=49
2x+2y*y'=0
y'=-x/y
2.√x+√y=10
1/(2√x)+1/(2√y)*y'=0
y'=-√(y/x)
3.(x-2)y^3=x+2
y^3*(x-2)+3y^2*y'=1
y'=[1-y^3*(x-2)]/(3y^2)
4.(x^2+y^2)^3=4x^5y^6
3(x^2+y^2)^2*(x^2+y^2)'=4(5x^4*y^6+6x^5*y^5*y')
3(x^2+y^2)^2*(2x+2y*y')=4(5x^4*y^6+6x^5*y^5*y')
6x(x^2+y^2)^2+6y(x^2+y^2)^2*y'=20x^4*y^6+24x^5*y^5*y'
y'=[20x^4*y^6-6x(x^2+y^2)^2]/[[6y(x^2+y^2)^2-24x^5*y^5]