Answer:
10x - 3y = -109 .
Step-by-step explanation:
x^2 + y^2 = 109
Implicit Differentiation:
2x + 2y.y' = 0
y' = -2x/2y = -x/y
So at the point (-10,3) the gradient of the tangent is -(-10)/3 = 10/3.
Equation of the tangent:
y - y1 = m(x - x1)
y - 3 = 10/3(x + 10)
y - 3 = 10/3 x + 100/3
3y - 9 = 10x + 100
-109 + 3y = 10x
10x - 3y = -109