-24ab+3(4a+b)² a=√7 b=√3

1) - 24ab + 3( 4a + b )^2 = - 24ab + 3( 16a^2 + 8ab + b^2 ) = - 24ab + 48a^2 + 24ab + 3b^2 = 48a^2 + 3b^2 = 3( 16a^2 + b^2 )
2) a = V 7 ; b = V 3
3( 16•7 + 3 ) = 3 • 115 = 345