a2 + b2 = 25 x2 + y2 = 17 ax + by = 10\(\sqrt {2}\) Find ay - bx:

33 25 15 10

15

Formula → (a2 + b2) (x2 + y2) = (ax + by)2 + (ay - bx)2 Let ay - bx = t 25 × 17 = (10\(\sqrt {2}\))2 + t2 425 = 200 + t2 t = \(\sqrt {225}\) = 15