Question

Thu gọn các đơn thức trong biểu thức đại số sau:

D = \(\dfrac{\left(3x^4y^4\right)^2.\left(\dfrac{1}{16}x^3y\right).\left(8x^{n-7}\right).\left(-2x^{7-n}\right)}{15x^3y^2.\left(0,4ax^2y^2z^2\right)^2}\) ( với axyz khác 0)

Answer 1

\(D=\dfrac{\left(3x^4y^4\right)^2\cdot\left(\dfrac{1}{16}x^3y\right)\cdot\left(8x^{n-7}\right)\cdot\left(-2x^{7-n}\right)}{15x^3y^2\cdot\left(0,4ax^2y^2z^2\right)^2}\)

\(=\dfrac{\left(3x^8y^8\right)\cdot\left(\dfrac{1}{16}x^3y\right)\cdot\left(8x^n:x^7\right)\cdot\left(-2x^7:x^n\right)}{15x^3y^2\cdot0,16a^2x^4y^4z^4}\)

\(=\dfrac{\left[3\cdot\dfrac{1}{16}\cdot8\cdot\left(-2\right)\right]\left[x^8\cdot x^3\left(x^7:x^7\right)\left(x^n:x^n\right)\right]\left(y^8y\right)}{\left(15\cdot0,16\cdot a^2\right)\left(x^3x^4\right)\left(y^2y^4\right)z^4}\)

\(=\dfrac{-3x^{11}y^9}{2,4a^2x^7y^6z^4}=\dfrac{-3x^4y^3}{2,4a^2z^4}\)