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Zorluk: OrtaOperations with Variable Exponents
When the algebraic expression
(3x−2y4)39x−5y2 \frac{(3x^{-2} y^4)^3}{9x^{-5} y^2}
is fully simplified to the form CxaybC x^a y^b (where CC, aa, and bb are constants), what is the value of bb?

Cevap: 10 / ten

Cevap

10
By distributing the outer exponent of 3 in the numerator using multiplication (4⋅34 \cdot 3) to get y12y^{12}, and then subtracting the denominator's exponent of 2 using the quotient rule (12−212 - 2), the final exponent on the variable yy is determined to be 10.

Adım Adım Çözüm

1
Apply the power of a product and power of a power rules to the numerator.
(3x−2y4)3=33⋅(x−2)3⋅(y4)3=27x−6y12(3x^{-2}y^4)^3 = 3^3 \cdot (x^{-2})^3 \cdot (y^4)^3 = 27x^{-6}y^{12}
When raising a product to a power, the outer power applies to each individual factor inside the parentheses. Exponents are multiplied when raising a power to another power.
2
Substitute the expanded numerator back into the fractional expression.
27x−6y129x−5y2 \frac{27x^{-6}y^{12}}{9x^{-5}y^2}
This sets up the expression for applying the quotient rule between the numerator and denominator.
3
Apply the quotient rule by dividing the coefficients and subtracting the exponents of like bases.
Coefficient: 27÷9=327 \div 9 = 3
Base xx: x−6−(−5)=x−6+5=x−1x^{-6 - (-5)} = x^{-6 + 5} = x^{-1}
Base yy: y12−2=y10y^{12 - 2} = y^{10}
When dividing exponential terms with the same base, subtract the denominator's exponent from the numerator's exponent.
4
Combine the simplified terms and identify the exponent bb.
The simplified expression is 3x−1y103x^{-1}y^{10}. Comparing this to the target form CxaybCx^a y^b, the value of bb is 1010.
This isolates the specific value requested by the question stem.

Anahtar Kavram

Power of a Power and Quotient of Powers Rules
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