Surds and Indices


  1. Solve the below equation.
    173.5 x 177.3 ÷ 174.2 = 17?











  1. View Hint View Answer Discuss in Forum

    173.5 x 177.3 ÷ 174.2 = 17?
    Apply the Laws of Exponents ::
    (am) x (an) = am+n
    Fractional Exponents ::
    am÷ a n=am?n
    ⇒ 173.5 + 7.3 - 4.2 = 17?

    Correct Option: C

    173.5 x 177.3 ÷ 174.2 = 17?
    Apply the Laws of Exponents ::
    (am) x (an) = am+n
    Fractional Exponents ::
    am÷ a n=am?n
    ⇒ 173.5 + 7.3 - 4.2 = 17?
    ⇒ 176.6 = 17?
    ? = 6.6


  1. Simplify ( 6a-2bc-3/4ab-3c2 ) ÷ ( 5a-3 b2c-1/3ab-2c3 )











  1. View Hint View Answer Discuss in Forum

    Given equation is,
    ( 6a-2bc-3/4ab-3c2 ) ÷ ( 5a-3 b2c-1/3ab-2c3 )
    Apply the algebra law a ÷ b = a x 1/b
    Apply the law of Fractional Exponents and Laws of Exponents
    (am)(an/) = am+n
    am÷an=am-n
    Or
    am/an=am-n
    Solve the equation.

    Correct Option: B

    Given equation is,
    ( 6a-2bc-3/4ab-3c2 ) ÷ ( 5a-3 b2c-1/3ab-2c3 )
    Apply the algebra law a ÷ b = a x 1/b
    = ( 6a-2bc-3/4ab-3c2 ) x ( 3ab-2c3/5a-3 b2c-1 )
    = ( 6a-2 bc-3 x 3ab-2c3) / ( 4ab-3c2 x 5a-3b2c-1 )
    Apply the law of Fractional Exponents and Laws of Exponents
    (am)(an) = am+n
    am÷an=am-n
    Or
    am/an=am-n
    = 18a-2 + 1 b1 - 2 c -3 + 3 / 20a1 - 3 b-3 + 2 c2 - 1
    = 9a-1b-1c0/ 10a - 2 b-1c1
    = ( 9/10 ) a-1 + 2b-1 + 1 c0 - 1
    = ( 9/10 ) a1b0 c-1
    = ( 9/10 ) ac-1 [∵ b0 = 1]



  1. The expression [(√2)2]2 gives









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    Given expression = [(√2)2]2
    = (√2)(2)2/2
    Apply the law of algebra formula and solve the equation.

    Correct Option: D

    Given expression = [(√2)2]2
    = (√2)(2)2/2
    = (√2)(2)1/√2
    = (2)1/2 x 21/√2
    = 2(2/21/√2)
    = (2)(2)(1/√2 - 1)
    which denotes a real number but not a rational number .


  1. If ( 5 + 2√3 ) / ( 7 + 4√3 ) = a + b√3, then the value of a and b is ?









  1. View Hint View Answer Discuss in Forum

    Given equation is,
    ( 5 + 2√3 ) / (7 + 4√3 )
    Now Multiply and divide by ( 7 - 4√3 ) in above given equation.
    By Rationalization, we will get,
    [ ( 5 + 2√3 ) / ( 7 + 4√3 ) ] x [ ( 7 - 4√3 ) / ( 7 - 4√3 ) ]
    [ ( 5 + 2√3 ) x ( 7 - 4√3 ) ] / [ ( 7 + 4√3 ) x ( 7 - 4√3 ) ]
    Apply the formula and multiplication rule of algebra,
    ( P + Q ) x (R - S ) = P x R - P x S + Q x R - Q x S .................(1)
    ( a + b ) x ( a - b) = a2 - b2......................................................(2)

    Correct Option: A

    Given equation is,
    ( 5 + 2√3 ) / (7 + 4√3 )
    Now Multiply and divide by ( 7 - 4√3 ) in above given equation.
    By Rationalization, we will get,
    [ ( 5 + 2√3 ) / ( 7 + 4√3 ) ] x [ ( 7 - 4√3 ) / ( 7 - 4√3 ) ]
    [ ( 5 + 2√3 ) x ( 7 - 4√3 ) ] / [ ( 7 + 4√3 ) x ( 7 - 4√3 ) ]
    Apply the formula and multiplication rule of algebra,
    ( P + Q ) x (R - S ) = P x R - P x S + Q x R - Q x S .................(1)
    ( a + b ) x ( a - b) = a2 - b2.......................................................(2)

    = ( 5 x 7 - 5 x 4√3 + 7 x 2√3 - 2√3 x 4√3 )/ ( 72 - (4√3)2 )
    = 35 - 20√3 + 14√3 - 8 x 3 / ( 49 - 16 x 3 )
    = ( 35 - 24 - 6√3 )/(49 - 48 )
    = 11 - 6√3
    ∵ ( 5 + 2√3 ) /( 7 + 4√3 ) = a + b√3
    ∴ a + b√3 = 11 - 6√3
    on equating the above equation and we get,
    or a = 11 and b = - 6



  1. 5 + ∛x = 3, then the value of x is ?









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    5 + ∛x = 3
    Apply the law of Algebra Law.
    Square both side of equation and solve the equation.

    Correct Option: A

    5 + ∛x = 3
    Apply the law of Algebra Law.
    Square both side of equation.
    (√5 + ∛x)2 = 32
    ⇒ 5 + ∛x = 9
    ⇒ ∛x = 9 - 5
    ⇒ ∛x = 4
    Now cube the both side of equation,
    ⇒ ( ∛x ) 3 = 43
    ⇒ x = (4)3
    ⇒ x = 64