Rút gọn biểu thức H = a a 3 a - 7 6 với a là số thực dương
A. H = 1 a 3
B. H = a 2
C. H = a 3
D. H = 1 a
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Đáp án B
P = a − 3 − 4 a − 1 a 1 2 − 4 a − 1 2 − 1 a − 1 2 = a 1 2 − 3 a − 1 2 − 4 a − 3 2 − a 1 2 + 4 a − 1 2 a − 1 2 ( a 1 2 − 4 a − 1 2 ) = a − 1 2 − 4 a − 3 2 1 − 4 a − 1 = a − 1 2
a) \(H=\left(\dfrac{a-3\sqrt{a}}{a-2\sqrt{a}-3}-\dfrac{2a}{a-1}\right):\dfrac{1-\sqrt{a}}{a-2\sqrt{a}+1}\)
\(H=\left[\dfrac{\sqrt{a}\left(\sqrt{a}-3\right)}{\left(\sqrt{a}-3\right)\left(\sqrt{a}+1\right)}-\dfrac{2a}{\left(\sqrt{a}+1\right)\left(\sqrt{a}-1\right)}\right]:\dfrac{1-\sqrt{a}}{\left(\sqrt{a}-1\right)^2}\)
\(H=\left[\dfrac{\sqrt{a}\left(\sqrt{a}-1\right)}{\left(\sqrt{a}-1\right)\left(\sqrt{a}+1\right)}-\dfrac{2a}{\left(\sqrt{a}+1\right)\left(\sqrt{a}-1\right)}\right]:\dfrac{-\left(\sqrt{a}-1\right)}{\left(\sqrt{a}-1\right)^2}\)
\(H=\dfrac{a-\sqrt{a}-2a}{\left(\sqrt{a}+1\right)\left(\sqrt{a}-1\right)}:\dfrac{-1}{\sqrt{a}-1}\)
\(H=\dfrac{-a-\sqrt{a}}{\left(\sqrt{a}+1\right)\left(\sqrt{a}-1\right)}\cdot-\left(\sqrt{a}-1\right)\)
\(H=\dfrac{-\sqrt{a}\left(\sqrt{a}+1\right)}{\left(\sqrt{a}-1\right)\left(\sqrt{a}+1\right)}\cdot-\left(\sqrt{a}-1\right)\)
\(H=\dfrac{\sqrt{a}\left(\sqrt{a}-1\right)}{\sqrt{a}-1}\)
\(H=\sqrt{a}\)
b) Thay x = 2023 vào ta có:
\(H=\sqrt{2023}\)
a: \(A=\dfrac{x^{\dfrac{1}{3}}\cdot y^{\dfrac{1}{2}}+y^{\dfrac{1}{3}}\cdot x^{\dfrac{1}{2}}}{x^{\dfrac{1}{6}}+y^{\dfrac{1}{6}}}=\dfrac{x^{\dfrac{1}{3}}\cdot y^{\dfrac{1}{3}}\left(x^{\dfrac{1}{6}}+y^{\dfrac{1}{6}}\right)}{x^{\dfrac{1}{6}}+y^{\dfrac{1}{6}}}=x^{\dfrac{1}{3}}\cdot y^{\dfrac{1}{3}}=\left(xy\right)^{\dfrac{1}{3}}\)
b: \(B=\dfrac{x^{3+\sqrt{3}}}{y^2}\cdot\dfrac{x^{-\sqrt{3}-1}}{y^{-2}}=\dfrac{x^{3+\sqrt{3}-\sqrt{3}-1}}{y^{2-2}}=x^2\)
\(H=\dfrac{a^2\left(a^{-2}b^3\right)^2\cdot b^{-1}}{\left(a^{-1}\cdot b\right)\cdot a^{-5}\cdot b^{-2}}\)
\(=\dfrac{a^2\cdot a^{-4}\cdot b^6\cdot b^{-1}}{a^{-1-5}\cdot b^{1-2}}\)
\(=\dfrac{a^{-2}\cdot b^5}{a^{-4}\cdot b^{-1}}=a^{-2+4}\cdot b^{5+1}=a^2b^6\)
\(H=\dfrac{a^2.a^{-4}.b^6.b^{-1}}{a^{-1}.b.a^{-5}.b^{-2}}=\dfrac{a^{2-4}.b^{6-1}}{a^{-1-5}.b^{1-2}}=\dfrac{a^{-2}.b^5}{a^{-6}.b^{-1}}=a^{-2-\left(-6\right)}.b^{5-\left(-1\right)}=a^4b^6\)
Đáp án C
a 7 + 1 . a 3 − 7 ( a 2 − 2 ) 2 + 2 = a 7 + 1 + 3 − 7 a ( 2 − 2 ) ( 2 + 2 ) = a 4 a − 2 = a 6
Đáp án C
a 7 + 1 . a 3 − 7 ( a 2 − 2 ) 2 + 2 = a 7 + 1 + 3 − 7 a ( 2 − 2 ) ( 2 + 2 ) = a 4 a − 2 = a 6