Algebra
- If p = 101, then the value of ³√p( p² - 3p + 3 ) - 1 is
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Using Rule 9,
Expression = ³√p( p² - 3p + 3 ) - 1
Expression = ³√( p³ - 3p² + 3p - 1
Expression = ³√(p - 1)³ = p - 1
Expression = 101 – 1 = 100Correct Option: A
Using Rule 9,
Expression = ³√p( p² - 3p + 3 ) - 1
Expression = ³√( p³ - 3p² + 3p - 1
Expression = ³√(p - 1)³ = p - 1
Expression = 101 – 1 = 100
- If p = 124, ³√p( p² + 3p + 3 ) + 1 is
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Using Rule 8,
Expression = ³√p( p² + 3p + 3 ) + 1
Expression = ³√( p³ + 3p² + 3p + 1
Expression = ³√(p + 1)³ = [ ( p + 1 )³ ]1 / 3 = ( p + 1 )
When p = 124,
Expression = p + 1 = 124 + 1 = 125Correct Option: D
Using Rule 8,
Expression = ³√p( p² + 3p + 3 ) + 1
Expression = ³√( p³ + 3p² + 3p + 1
Expression = ³√(p + 1)³ = [ ( p + 1 )³ ]1 / 3 = ( p + 1 )
When p = 124,
Expression = p + 1 = 124 + 1 = 125
- If p – 2q = 4, then the value of p³ – 8q³ – 24pq – 64 is :
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Using Rule 9,
p – 2q = 4
On cubing both sides,
(p – 2q)3 = 64
⇒ p3 - 8q3 + 3p.4q2 - 3p2.2q = 64
⇒ p3 - 8q3 + 12pq2 - 6p2q = 64
⇒ p3 - 8q3 + 6pq(p – 2q) = 64
⇒ p3 - 8q3 + 6pq × 4 = 64
⇒ p3 - 8q3 – 24pq – 64 = 0Correct Option: B
Using Rule 9,
p – 2q = 4
On cubing both sides,
(p – 2q)3 = 64
⇒ p3 - 8q3 + 3p.4q2 - 3p2.2q = 64
⇒ p3 - 8q3 + 12pq2 - 6p2q = 64
⇒ p3 - 8q3 + 6pq(p – 2q) = 64
⇒ p3 - 8q3 + 6pq × 4 = 64
⇒ p3 - 8q3 – 24pq – 64 = 0
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If x = 19 and y = 18, then the value of x2 + y2 + xy is : x3 - y3
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Expression = x2 + y2 + xy x3 - y3 Expression = x2 + y2 + xy = 1 (x - y)(x2 + y2 + xy) (x - y) Expression = 1 = 1 19 - 18 Correct Option: A
Expression = x2 + y2 + xy x3 - y3 Expression = x2 + y2 + xy = 1 (x - y)(x2 + y2 + xy) (x - y) Expression = 1 = 1 19 - 18
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If x + 1 = 2 and x is real, then the value of x17 + 1 is x x19
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x + 1 = 2 x
⇒ x2 - 2x + 1 = 0
⇒ ( x - 1 )2 = 0 ⇒ x = 1∴ x17 + 1 = 1 + 1 = 2 x19
Second Method :-Here, x + 1 = 2 x
By Hit and trial method , putting x = 1∴ x17 + 1 = 2 x19 Correct Option: C
x + 1 = 2 x
⇒ x2 - 2x + 1 = 0
⇒ ( x - 1 )2 = 0 ⇒ x = 1∴ x17 + 1 = 1 + 1 = 2 x19
Second Method :-Here, x + 1 = 2 x
By Hit and trial method , putting x = 1∴ x17 + 1 = 2 x19