Find the tangent equation of the curve y = 4x-x ^ 2 at point B (1,3)

Find the tangent equation of the curve y = 4x-x ^ 2 at point B (1,3)

For the equation where the slope is obtained by deriving y, the value of the slope at B is obtained by taking x = 1, and then the tangent equation is obtained by using the point oblique formula