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CUET
General Aptitude Test
Quantitative Reasoning
Algebra
a2 + b2 = 25
x2 + y2 = 17
ax + by = 10\(\sqrt {2}\)
Find ay - bx:
33
25
15
10
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
