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The value of y for which distance between points P(2, 3) and Q(0, y) is 10 unit, is :(A) -9 or -3(B) 9 or -3(C) 9 or 3(D) -4 or 9 |
Answer» Answer is (B) 9 or -3 Distance between P(2, 3) and Q(10, y) = 10 √((10 - 2)2 + (y - 3)2) = 10 square both sides ⇒ (8)2 + (y – 3)2 = 100 ⇒ (y – 3)2 = 100 – 64 ⇒ (y – 3)2 = 36 ⇒ y – 3 = ±6 Taking the +ve sign y – 3 = 6 y = 6 + 3 = 9 Taking -ve sign y – 3 = -6 y = -6 + 3 = -3 So y = 9 or -3 |
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