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1: \(A=\dfrac{\left(\sqrt{x}+2\right)\left(\sqrt{x}-2\right)-5-\sqrt{x}-3}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+3\right)}\)

\(=\dfrac{x-4-\sqrt{x}-8}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+3\right)}=\dfrac{x-\sqrt{x}-12}{\left(\sqrt{x}-2\right)\left(\sqrt{x}+3\right)}\)

\(=\dfrac{\sqrt{x}-4}{\sqrt{x}-2}\)

15 tháng 5 2023

\(T=\dfrac{\sqrt{27}+3}{\sqrt{3}}=\dfrac{3\sqrt{3}+3}{\sqrt{3}}=\dfrac{3\left(\sqrt{3}+1\right)}{\sqrt{3}}=\sqrt{3}\left(\sqrt{3}+1\right)=3+\sqrt{3}\)

15 tháng 5 2023

Dạ √27 + 3 / √3 ạ 3 với căn 3 là chung với nhau ý ạ chứ ko phải như trên ý ạ

 

13 tháng 11 2021

\(B=9x^4-\left(2x+1\right)^2-\left(9x^4+6x^2+1\right)\\ =9x^4-4x^2-4x-1-9x^4-6x^2-1\\ =-10x^2-4x-2\)

13 tháng 11 2021

sai r \(\left(3x^2-2x+1\right)\left(3x^2+2x+1\right)=\left[3x^2-\left(2x-1\right)\right]\left[3x^2+\left(2x+1\right)\right]\)

19 tháng 10 2021

\(15,A=\dfrac{x-1-4\sqrt{x}+4+1}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}\cdot\dfrac{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}\left(\sqrt{x}-2\right)}\\ A=\dfrac{\left(\sqrt{x}-2\right)^2}{\sqrt{x}\left(\sqrt{x}-2\right)}=\dfrac{\sqrt{x}-2}{\sqrt{x}}\\ 16,B=\dfrac{\sqrt{x}\left(x\sqrt{x}-1\right)}{x+\sqrt{x}+1}-\dfrac{2\sqrt{x}\left(\sqrt{x}+1\right)}{\sqrt{x}}+\dfrac{2\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}{\sqrt{x}-1}\\ B=\dfrac{\sqrt{x}\left(\sqrt{x}-1\right)\left(x+\sqrt{x}+1\right)}{x+\sqrt{x}+1}-2\left(\sqrt{x}+1\right)+2\left(\sqrt{x}+1\right)\\ B=x-\sqrt{x}-2\sqrt{x}-2+2\sqrt{x}+2=x-\sqrt{x}\)

19 tháng 10 2021

15. \(=\dfrac{x-1-4\left(\sqrt{x}-1\right)+1}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}.\dfrac{x-1}{\sqrt{x}\left(\sqrt{x}-2\right)}\\ =\dfrac{x-4\sqrt{x}+4}{x-1}.\dfrac{x-1}{\sqrt{x}\left(\sqrt{x}-2\right)}\\ =\left(\sqrt{x}-2\right)^2.\dfrac{1}{\sqrt{x}\left(\sqrt{x}-2\right)}=\dfrac{\sqrt{x}-2}{\sqrt{x}}\)

 

NV
9 tháng 5 2021

\(C=\dfrac{\left(\sqrt{a}-1\right)\left(\sqrt{a}+1\right)}{\sqrt{a}-1}-\dfrac{\left(\sqrt{a}-1\right)\left(a+\sqrt{a}+1\right)}{\left(\sqrt{a}-1\right)\left(\sqrt{a}+1\right)}\)

\(=\dfrac{\left(\sqrt{a}+1\right)^2}{\sqrt{a}+1}-\dfrac{a+\sqrt{a}+1}{\sqrt{a}+1}=\dfrac{a+2\sqrt{a}+1-a-\sqrt{a}-1}{\sqrt{a}+1}\)

\(=\dfrac{\sqrt{a}}{\sqrt{a}+1}\)

7 tháng 10 2021

a) \(\sqrt{0,64.a^2}\left(a>0\right)=0,8.\left|a\right|=0,8a\)

b) \(\sqrt{a^2\left(a-2\right)^2}\left(a>2\right)=\left|a\left(a-2\right)\right|=a\left(a-2\right)=a^2-2a\)

c) \(\dfrac{1-a\sqrt{a}}{1-\sqrt{a}}\left(a\ge0,a\ne1\right)=\dfrac{\left(1-\sqrt{a}\right)\left(1+\sqrt{a}+a\right)}{1-\sqrt{a}}=1+\sqrt{a}+a\)

8 tháng 5 2021

\(\dfrac{2sin8a-sin16a}{2sin8a+sin16a}=\dfrac{2sin8a-2sin8a.cos8a}{2sin8a+2sin8a.cos8a}=\dfrac{2sin8a\left(1-cos8a\right)}{2sin8a\left(1+cos8a\right)}=\dfrac{1-cos8a}{1+cos8a}=\dfrac{1-\left(1-2sin^24a\right)}{1+\left(1-2sin^24a\right)}=\dfrac{2sin^24a}{2-2sin^24a}=\dfrac{sin^24a}{1-sin^24a}=\dfrac{sin^24a}{cot^24a}=tan^24a\)

NV
8 tháng 5 2021

\(=\dfrac{2sin8a-2sin8a.cos8a}{2sin8a+2sin8a.cos8a}=\dfrac{2sin8a\left(1-cos8a\right)}{2sin8a\left(1+cos8a\right)}=\dfrac{1-cos8a}{1+cos8a}\)

\(=\dfrac{1-\left(1-2sin^24a\right)}{1+\left(2cos^24a-1\right)}=\dfrac{2sin^24a}{2cos^24a}=tan^24a\)