Find the extreme values of f on the region described by the inequality. f(x, y) = x2 + y2 + 4x − 4y, x2 + y2 ≤ 49

0, and the normal line is given by  x(t) = 〈0, 0, 1〉 + 〈1, 1, 1〉 t. 2.  findthe equation of the tangent plane to the ellipsoid  x2  a2. +  y2  b2. + z2 c2. = 1 and we need only maximize this on the domain  x2  +  y2 ≤  r2.   find  the  extreme values  of  f(x,  y) =  x2  +  y2  +  4x − 4y  on theregion x2  +  y2 ≤  9.