posted by Kevin .
Find the equation of the tangent line to the curve (a lemniscate) 2(x^2+y^2)^2 = 25(x^2-y^2) at the point ( -3 , -1 )
differentiate implicitly with respect to x and solve for dy/dx
sub in the point (-3,-1) to get the slope
now use the grade 9 way of finding the equation of a straight line