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Zorluk: OrtaProperties of Exponents in Algebraic Expressions
If xx and yy are positive real numbers such that
(x3y−2)k⋅(x−1y4)3=x6y6(x^3 y^{-2})^k \cdot (x^{-1} y^4)^3 = x^6 y^6
what is the value of the exponent kk?

Cevap: 3

Cevap

The value of the exponent kk is 3.
Applying the exponent rules simplifies the left side of the equation to x3k−3y12−2kx^{3k-3}y^{12-2k}. Equating the exponent of xx to the right side gives 3k−3=63k - 3 = 6, which yields k=3k = 3. This value is confirmed by equating the exponent of yy, since 12−2(3)=612 - 2(3) = 6.

Adım Adım Çözüm

1
Apply the power of a power rule (am)n=amn(a^m)^n = a^{mn} to expand the terms in the expression.
(x3y−2)k=x3ky−2k(x^3 y^{-2})^k = x^{3k} y^{-2k} and (x−1y4)3=x−3y12(x^{-1} y^4)^3 = x^{-3} y^{12}
To remove the outer parentheses by multiplying the internal exponents of each variable by the outer exponent.
2
Multiply the terms together by applying the product rule for exponents, am⋅an=am+na^m \cdot a^n = a^{m+n}.
(x3ky−2k)(x−3y12)=x3k−3y12−2k(x^{3k} y^{-2k})(x^{-3} y^{12}) = x^{3k-3} y^{12-2k}
To combine the like bases of xx and yy into a single simplified expression.
3
Set the exponents of like bases equal to the exponents on the right-hand side of the equation, x6y6x^6 y^6.
3k−3=63k - 3 = 6 and 12−2k=612 - 2k = 6
Since the bases are equal and non-zero, their respective exponents must also be equal.
4
Solve the linear equation 3k−3=63k - 3 = 6 for kk.
3k=9  ⟹  k=33k = 9 \implies k = 3
To determine the numerical value of the variable kk.
5
Verify the solution by solving the second linear equation, 12−2k=612 - 2k = 6.
−2k=−6  ⟹  k=3-2k = -6 \implies k = 3
To ensure consistency across both variable exponents in the expression.

Anahtar Kavram

Properties of Exponents in Algebraic Expressions
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