Algebra
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If x = y = z , then b + c c + a a + b
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x = y b + c b + a = x - y = x - y ; y = z b + c - c -a b - a c + a a + b = y - z = y - z ; z = x c + a - a - b c - b a + b b + c = z - x = z - x a + b - b - c a - c ∴ x - y = y - z = z - x b - a c - b a - c Correct Option: A
x = y b + c b + a = x - y = x - y ; y = z b + c - c -a b - a c + a a + b = y - z = y - z ; z = x c + a - a - b c - b a + b b + c = z - x = z - x a + b - b - c a - c ∴ x - y = y - z = z - x b - a c - b a - c
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If x = 3 + 2√2 and xy = 1, then the value of x2 + 3xy + y2 is x2 − 3xy + y2
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x = 3 + 2√2
⇒ xy = 1⇒ y = 1 = 1 × 3 - 2√2 3 + 2√2 3 + 2√2 3 - 2√2 = 3 - 2√2 = 3 - 2√2 9 - 8
∴ x + y
= 3 + 2√2 + 3 - 2√2 = 6∴ x² + 3xy + y² = (x + y)² + xy x² - 3xy + y² (x - y)² - 5xy = 36 + 1 = 37 36 - 5 31 Correct Option: D
x = 3 + 2√2
⇒ xy = 1⇒ y = 1 = 1 × 3 - 2√2 3 + 2√2 3 + 2√2 3 - 2√2 = 3 - 2√2 = 3 - 2√2 9 - 8
∴ x + y
= 3 + 2√2 + 3 - 2√2 = 6∴ x² + 3xy + y² = (x + y)² + xy x² - 3xy + y² (x - y)² - 5xy = 36 + 1 = 37 36 - 5 31
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If x2 + 5x + 6 = 0, then the value of 2x is : x2 − 7x + 6
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Given, x2 + 5x + 6 = 0
∴ Expression = 2x x2 − 7x + 6 = 2x = 2 x2 + 5x + 6 − 12x −12 = −1 6 Correct Option: C
Given, x2 + 5x + 6 = 0
∴ Expression = 2x x2 − 7x + 6 = 2x = 2 x2 + 5x + 6 − 12x −12 = −1 6
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If a + b + c = 1 , then the value of 1 − 2a 1 − 2b 1 − 2c 2 1 + 1 + 1 is : 1 − 2a 1 − 2b 1 − 2c
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a + b + c = 1 1 − 2a 1 − 2b 1 − 2c 2 ⇒ 2a + 2b + 2c = 2 = 1 1 − 2a 1 − 2b 1 − 2c 2 ⇒ 2a + 1 + 2b + 1 + 2c + 1 = 4 1 − 2a 1 − 2b 1 − 2c ⇒ 2a + 1 − 2a + 2b + 1 − 2b + 2c + 1 − 2c = 4 1 − 2a 1 − 2b 1 − 2c ⇒ 1 + 1 + 1 = 4 1 − 2a 1 − 2b 1 − 2c Correct Option: D
a + b + c = 1 1 − 2a 1 − 2b 1 − 2c 2 ⇒ 2a + 2b + 2c = 2 = 1 1 − 2a 1 − 2b 1 − 2c 2 ⇒ 2a + 1 + 2b + 1 + 2c + 1 = 4 1 − 2a 1 − 2b 1 − 2c ⇒ 2a + 1 − 2a + 2b + 1 − 2b + 2c + 1 − 2c = 4 1 − 2a 1 − 2b 1 − 2c ⇒ 1 + 1 + 1 = 4 1 − 2a 1 − 2b 1 − 2c
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If p2 + 1 = 47, the value of p + 1 is : p2 p
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p2 + 1 = 47 p2 ⇒ p + 1 2 – 2 = 47 p ⇒ p + 1 2 = 47 + 2 = 49 p ⇒ p + 1 = √49 = 7 p Correct Option: C
p2 + 1 = 47 p2 ⇒ p + 1 2 – 2 = 47 p ⇒ p + 1 2 = 47 + 2 = 49 p ⇒ p + 1 = √49 = 7 p