If a and b are integers of opposite signs such that (a + 3)2 : b2 = 9 : 1 and (a - 1)2: (b - 1)2 = 4 : 1, then the ratio a2 : b2 is:
Explanation:
a+3b2=9 and a-1b-12=4
⇒ a+3b=±3 and a-1b-1=±2
We get following cases:
Case 1(a): a + 3 = 3b and a - 1 = 2b - 2 ⇒ a = 3 and b = 2 (Rejected)
Case 1(b): a + 3 = 3b and a - 1 = -2b + 2 ⇒ b is not an integer (Rejected)
Case 2(a): a + 3 = -3b and a - 1 = 2b - 2 ⇒ b is not an integer (Rejected)
Case 2(b): a + 3 = -3b and a - 1 = -2b + 2 ⇒ a = 15 and b = -6 ∴ (a/b)2 = (15/-6)2 = 25/4
Hence, option (d).
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