Question 252311
Given,  ac + bd = 19 and ad −bc = 94 
Therefore, (ac+bd)^2+(ad-bc)^2 = (19)^2+(94)^2
           a^2c^2+b^2d^2+2abcd+a^2d^2+b^2c^2-2abcd = 361+8836
           (a^2+b^2)(c^2+d^2) = 9197