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? asked in Science & MathematicsMathematics · 1 month ago

How do you simplify z^-2 / z^-3?

At this point it's confirmed that I suck at math.

21 Answers

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  • 1 month ago
    Favourite answer

    Hint

    a^x * a^y = a^(x + y)

    a^x / a^y = a^(x - y)

  • ?
    Lv 7
    1 month ago

    Since the base is the same just subtract the exponents. 

     A negative exponent means you have a fraction

    Go back to the method you used when dividing a common fraction by a common fraction

    z^-2 = 1 / z^2

    z^-3 = 1 / z ^3

    Do you remember the rule: invert and multiply?

    [1 / z^2] / [1 / z^3] = [1 / z^2] X [z^3 / 1] 

  • 1 month ago

    multiple z means snoozing.

  • ?
    Lv 7
    1 month ago

    In a a ratio, if the bases are the same, subtract the exponents.

    (-2) - (-3) = 1  therefore z to the first power. QED

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  • Jim
    Lv 7
    1 month ago

    First, invert both to get rid of negative exponents: 

    z⁻²/z⁻³ = z³/z²

    Now reduce: (z²/z²)*z¹ = 1*z

    = z

  • 1 month ago

    Go back to law of exponents:

    When multiplying two powers of the same base (here, the base is "z"), just add the powers.

    example:  z^2 * z^4 = zz * zzzz = zzzzzz = z^6

    z^2 * x^4 = z^(2+4) = z^6

    When dividing two powers (of the same base), subtract the powers

    z^5 / z^2 = zzzzz / zz = zz*zzz / zz = zzz = z^3

    z^5 / z^2 = z^(5-2) = z^3

    z^0 = 1

    This comes from the second rule.

    Anything divided by itself = 1

    z^4 / z^4 = 1

    z^4 / z^4 = z^(4-4) = z^0

    A negative power is a "reciprocal" (a fraction)

    1 / z^3 = z^0 / z^3 = z^(0-3) = z^(-3)

    -----

    Your problem  begins as a case for the second rule (division)

    just be careful with signs

    z^(-2) / z^(-3) = z^(-2 - -3) = z^(-2+3) = z^1 = z

  • 1 month ago

    Remember z^-2 = 1/z^2 

    Similarly z^-3 = 1/z^3 

    Hence [ 1/z^2]/ [1/z^3]  is division of fractions. 

    Hence 

    [1/z^2] x [z^3/1]

    Cancel down by 'z^2' 

    Hence 

    1/1 x z/1 = 'z^1' = 'z'   The answer  

  • Pope
    Lv 7
    1 month ago

    Hardly anyone gets these right. Try multiplying numerator and denominator both by z³, but do be careful.

    z⁻² / z⁻³

    = (z⁻² / z⁻³)(z³ / z³) ... where z ≠ 0

    = z³⁻² / z³⁻³

    = z¹ / z⁰

    = z

    z⁻² / z⁻³ = z, where z ≠ 0

    Without that exclusion, the answer z would be incorrect, or at least incomplete. In the first step, the denominator is multiplied by z³. If z were zero, that would be division by zero, an invalid operation. The given expression is undefined at z = 0. No amount of simplification can change that.

  • ?
    Lv 7
    1 month ago

    Note that except for Daniel H answer, the others are wrong and made mistakes. 

  • 1 month ago

    When you have a negative exponent, you can swap it to the other side of the fraction and change the sign. So z^-2 would change to z^2 in the denominator. Likewise, z^-3 in the denominator would become z^3 in the numerator.

    So this would turn into:

    z^3 / z^2

    At that point you can reduce this. When you divide two numbers (with the same base), you subtract the exponents:

    = z^(3-2)

    = z^1

    = z

    Answer:

    z (as long as z ≠ 0)

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