Rút gọn biểu thức ( nhanh giúp mình nha)
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d: \(\dfrac{-\left(\sqrt{3}-\sqrt{6}\right)}{1-\sqrt{2}}+\dfrac{6\sqrt{3}+3}{\sqrt{3}}-\dfrac{13}{4+\sqrt{3}}\)
\(=-\sqrt{3}+6+\sqrt{3}-4+\sqrt{3}\)
\(=2+\sqrt{3}\)
a)B = ( 2 + 4 + 6 + 8 +........+ 2014 ) - ( 3 + 5 + 7 + 9 +.......+ 2011 )
= 1015056 - 1012035
= 3021
Mk nhanh nhất đó
a: Ta có: \(\left(x+y\right)^2+\left(x-y\right)^2-2x^2\)
\(=x^2+2xy+y^2+x^2-2xy+y^2-2x^2\)
\(=2y^2\)
b: Ta có: \(\left(x+1\right)^3-\left(x-1\right)\left(x^2+x+1\right)-3x\left(x+1\right)\)
\(=x^3+3x^2+3x+1-x^3+1-3x^2-3x\)
=2
\(ĐKXĐ:x\ne16\)
\(Q=\frac{1+3\sqrt{x}-12}{\sqrt{x}-4}.\frac{\left(\sqrt{x}-4\right)\left(\sqrt{x}+4\right)}{3-\sqrt{x}-11}\)
\(=\frac{\left(3\sqrt{x}-11\right)\left(\sqrt{x}+4\right)}{-\sqrt{x}-8}\)
\(\left(\frac{1}{\sqrt{x}-4}+3\right).\frac{x-16}{3-\sqrt{x}-11}=\left(\frac{1}{\sqrt{x}-4}+\frac{3\left(\sqrt{x}-4\right)}{\sqrt{x}-4}\right).\frac{\left(\sqrt{x}-4\right)\left(\sqrt{x}+4\right)}{-\sqrt{x}-8}\)
\(=\frac{1+3\left(\sqrt{x}-4\right)}{\sqrt{x}-4}.\frac{\left(\sqrt{x}-4\right)\left(\sqrt{x}+4\right)}{-\sqrt{x}-8}=\frac{1+3\sqrt{x}-12}{\sqrt{x}-4}.\frac{\left(\sqrt{x}-4\right)\left(\sqrt{x}+4\right)}{-\sqrt{x}-8}\)
\(=\frac{3\sqrt{x}-11}{\sqrt{x}-4}.\frac{\left(\sqrt{x}-4\right)\left(\sqrt{x}+4\right)}{-\left(\sqrt{x}+8\right)}=\frac{\left(3\sqrt{x}-11\right)\left(\sqrt{x}+4\right)}{-\left(\sqrt{x}+8\right)}\)
1: \(=\dfrac{1}{\sqrt{2}}\cdot\left(\sqrt{2x-2\sqrt{2x-1}}-\sqrt{2x+2\sqrt{2x-1}}\right)\)
\(=\dfrac{1}{\sqrt{2}}\left(\left|\sqrt{2x-1}-1\right|-\left|\sqrt{2x-1}+1\right|\right)\)
TH1: x>=1
\(A=\dfrac{1}{\sqrt{2}}\left(\sqrt{2x-1}-1-\sqrt{2x-1}-1\right)=-\sqrt{2}\)
TH2: 1/2<=x<1
\(A=\dfrac{1}{\sqrt{2}}\left(1-\sqrt{2x-1}-\sqrt{2x-1}-1\right)=-\sqrt{4x-2}\)
2:
\(=\sqrt{x-1+6\sqrt{x-1}+9}-\sqrt{x-2-2\sqrt{x-2}+1+3}\)
\(=\sqrt{x-1}+3-\sqrt{\left(\sqrt{x-2}-1\right)^2+3}\)
\(\left(a+b\right)^2-\left(a-b\right)^2\)
\(=\left[a+b-\left(a-b\right)\right]\left[a+b+a-b\right]\)
\(=2b\cdot2a\)
\(=4ab\)
a) \(=x^2+2x-2x=x^2\)
b) \(=4-x^2+x^2=4\)
c) \(=x^2-x^3+x^3+27=x^2+27\)
d) \(=4x^2+4xy+y^2+4x^2-8x^2-4xy=y^2\)