`3/(4x-20)+15/(50-2x^2)+7/(6x+30)=0(x ne +-5)`
`pt<=>3/(4(x-5))+15/(2(5-x)(5+x))+7/(6(x+5))=0`
`<=>3/(4(x-5))+7/(6(x+5))-15/(2(x-5)(x+5))=0`
`<=>9(x+5)+14(x-5)-90=0`
`<=>9x+45+14x-70-90=0`
`<=>23x=115`
`<=>x=5(ktm)`
Vậy PTVN
2.tìm x
a)\(\sqrt{x^2-6x+9}\)
b)\(\sqrt{x^2-2x+1}\)
c)\(\sqrt{4x+12}-3\sqrt{x+3}+7\sqrt{9x+27}=20\)
d)\(\sqrt{4x+20}+3\sqrt{\dfrac{x-5}{9}}-\dfrac{1}{3}\sqrt{9x-45}=6\)
Rút gọn
a) \(\dfrac{x^5-2x^4+2x^3-4x^2-3x+6}{x+4}\)
b) \(\dfrac{x^4-4x^2+3}{x^4+6x^2-7}\)
c) \(\dfrac{x^4+x^3-x-1}{x^4+x^3+2x^2+x+1}\)
1. Cho \(a^3+b^3+c^3=3abc\) (a+b+c ≠0)
Tính giá trị biểu thức:
\(M=\dfrac{a^2+b^2+c^2}{\left(a+b+c\right)^2}\)
2. Rút gọn
a) \(\dfrac{x^3+x^2-6x}{x^3-4x}\)
b) \(\dfrac{x^2+8x+7}{x^3+2x^2+x}\)
a) \(\sqrt{4x+20}+\sqrt{x+5}-\dfrac{1}{3}\sqrt{9x+45}=4\)
b) \(\sqrt{36x-36}-\sqrt{9x-9}-\sqrt{4x-4}=16-\sqrt{x-1}\)
c) \(\sqrt{x^2+6x-9}-2\sqrt{x^2-2x+1}+\sqrt{x^2}=0\)
Giải phương trình:
a) \(\sqrt{x+3}+\dfrac{4x}{\sqrt{x+3}}=4\sqrt{x}\)
b \(2x^4-5x^3+6x^2-5x+2=0\)
a) \(\sqrt{4x^2-9}=2\sqrt{x+3}\)
b) \(\sqrt{4x+20}+3\sqrt{\dfrac{x-5}{9}}-\dfrac{1}{3}\sqrt{9x-45}=4\)
c) \(\dfrac{2}{3}\sqrt{9x-9}-\dfrac{1}{4}\sqrt{16x-16}+27\sqrt{\dfrac{x-1}{81}}=4\)
d)\(5\sqrt{\dfrac{9x-27}{25}}-7\sqrt{\dfrac{4x-12}{9}}-7\sqrt{x^2-9}+18\sqrt{\dfrac{9x^2-81}{81}}=0\)
\(\dfrac{3}{1-4x}+\dfrac{8+6x}{16x^2-1}=\dfrac{2}{4x+1}\)
Giải phương trình:
a)\(\sqrt{\sqrt{5}-\sqrt{3x}}=\sqrt{8+2\sqrt{15}}\)
b)\(\sqrt{4x-20}-3\sqrt{\dfrac{x-5}{9}}=\sqrt{1-x}\)
c) \(\sqrt{4x+8}+2\sqrt{x+2}-\sqrt{9x+18}=1\)
d) \(\sqrt{x^2-6x+9}+x=11\)
e) \(\sqrt{3x^2-4x+3}=1-2x\)
f) \(\sqrt{16\left(x+1\right)}-\sqrt{9\left(x+1\right)}=4\)
g) \(\sqrt{9x+9}+\sqrt{4x+4}=\sqrt{x+1}\)
a)\(\dfrac{x^2}{\sqrt{5}}\) - \(\sqrt{20}\)=0
b)\(3\sqrt{2x}+\dfrac{1}{7}\)\(\sqrt{98}\) - \(\sqrt{72}+4=0\)
