A^2-9b^2/4a^2*a/4a+12b . При а=√2 b=√18

Question

A^2-9b^2/4a^2*a/4a+12b . При а=√2 b=√18

Answer 1

(а²-9b²)/(4a²) * a/(4a+12b)=((a-3b)(a+3b)) / (4*4a(a+3b))=(a-3b)/16a

при   а=√2,  b=√18

(√2 -3√18)/(16√2)=(√2-9√2)/16√2 = ( - 8√2)/(16√2)= - 1/2= - 0,5