Algebra
- If x , y, and z are real numbers such that (x – 3)2 + (y – 4)2 + (z – 5)2 = 0 then, (x + y + z) is equal to
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If a2 + b2 + c2 = 0 then, a = 0, b = 0 and c = 0
∴ (x – 3)2 + (y – 4)2 + (z – 5)2 = 0
∴ x – 3 = 0 ⇒ x = 3
y – 4 = 0 ⇒ y = 4
z – 5 = 0 ⇒ z = 5
∴ x + y + z = 3 + 4 + 5 = 12Correct Option: D
If a2 + b2 + c2 = 0 then, a = 0, b = 0 and c = 0
∴ (x – 3)2 + (y – 4)2 + (z – 5)2 = 0
∴ x – 3 = 0 ⇒ x = 3
y – 4 = 0 ⇒ y = 4
z – 5 = 0 ⇒ z = 5
∴ x + y + z = 3 + 4 + 5 = 12
- If (x – 4)(x2 + 4x + 42) = x3 - p, then p is equal to
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a3 – b3 = (a – b)(a2 + ab + b2)
∴ (x – 4)(x2 + 4x + 42) = x3 - 43 = x3 - 64
⇒ x3 - p = x3 - 64
⇒ p = 64Correct Option: C
a3 – b3 = (a – b)(a2 + ab + b2)
∴ (x – 4)(x2 + 4x + 42) = x3 - 43 = x3 - 64
⇒ x3 - p = x3 - 64
⇒ p = 64
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The simplified value of 1 - 2xy ÷ x3 - y3 - 3xy is x2 + y2 x - y
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Expression = 1 - 2xy ÷ x3 - y3 - 3xy x2 + y2 x - y Expression = x2 + y2 - 2xy ÷ (x - y)(x2 + xy + y2) - 3xy x2 + y2 x - y Expression = (x - y)2 ÷ (x2 + xy + y2 - 3xy) x2 + y2 Expression = (x - y)2 ÷ (x2 - 2xy + y2) x2 + y2 Expression = (x - y)2 ÷ (x - y)2 x2 + y2 Expression = 1 x2 + y2
Correct Option: B
Expression = 1 - 2xy ÷ x3 - y3 - 3xy x2 + y2 x - y Expression = x2 + y2 - 2xy ÷ (x - y)(x2 + xy + y2) - 3xy x2 + y2 x - y Expression = (x - y)2 ÷ (x2 + xy + y2 - 3xy) x2 + y2 Expression = (x - y)2 ÷ (x2 - 2xy + y2) x2 + y2 Expression = (x - y)2 ÷ (x - y)2 x2 + y2 Expression = 1 x2 + y2
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If a + b + c = 0 then the value of 1 + 1 + 1 is (a + b)(b + c) (b + c)(c + a) (c + a)(a + b)
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1 + 1 + 1 = c + a + a + b + b + c (a + b)(b + c) (b + c)(c + a) (c + a)(a + b) (a + b)(b + c)(c + a) 1 + 1 + 1 = 2(a + b + c) = 0 (a + b)(b + c) (b + c)(c + a) (c + a)(a + b) (a + b)(b + c)(c + a) Correct Option: A
1 + 1 + 1 = c + a + a + b + b + c (a + b)(b + c) (b + c)(c + a) (c + a)(a + b) (a + b)(b + c)(c + a) 1 + 1 + 1 = 2(a + b + c) = 0 (a + b)(b + c) (b + c)(c + a) (c + a)(a + b) (a + b)(b + c)(c + a)
- If x2 + y2 + 2x + 1 = 0, then the value of x31 + y35 is
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x2 + y2 + 2x + 1 = 0
⇒ x2 + 2x + 1 + y2 = 0
⇒ (x + 1)2 + y2 = 0
∴ x + 1 = 0 ⇒ x = –1 and y = 0
∴ x31 + y35 = (-1)31 + 0 = -1Correct Option: A
x2 + y2 + 2x + 1 = 0
⇒ x2 + 2x + 1 + y2 = 0
⇒ (x + 1)2 + y2 = 0
∴ x + 1 = 0 ⇒ x = –1 and y = 0
∴ x31 + y35 = (-1)31 + 0 = -1