2.11.10 Function Extrema

Condition: Find the conditional extremums of the functions: \ [\ begin {array} {l} l (x, y) = a x^{2} +2 x y+b y^{2}, 4 x {2}+C y^{2} = 9, \\ A = 7, \ QUAD B = 4, \ Quadad C = 2. \ end {Array} \]