\(15\left(x+9\right)\left(x-3\right)\left(x+21\right)=0\)
\(\Leftrightarrow\left(15x+135\right)\left(x-3\right)\left(x+21\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}15x+135=0\\x-3=0\\x+21=0\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=-9\\x=3\\x=-21\end{matrix}\right.\)
Vậy ...................
GIải phương trình sau:
a) \(\left(x-1\right)^3+\left(2x+3\right)^3=27x^3+8\)
b) \(\left(x^2+1\right)^2+3x\left(x^2+1\right)+2x^2=0\)
Tìm x biết :
a) \(\left(x-2\right)^3+6\left(x+1\right)^2-x^3+12=0\)
b) \(\left(x-5\right)\left(x+5\right)-\left(x+3\right)^3+3\left(x-2\right)^2=\left(x+1\right)^2-\left(x+4\right)\left(x-4\right)+3x^2\)
c) \(\left(2x+3\right)^2+\left(x-1\right)\left(x+1\right)=5\left(x+2\right)^2-\left(x-5\right)\left(x+1\right)+\left(x+4\right)^2\)
d) \(\left(1-3x\right)^2-\left(x-2\right)\left(9x+1\right)=\left(3x-4\right)\left(3x+4\right)-9\left(x+3\right)^2\)
Giải phương trình:
\(x^2-4-\left(x+5\right).\left(2-x\right)=0\)
Giải hệ phương trình : \(\left\{{}\begin{matrix}\dfrac{y}{x+\dfrac{5}{3}}\\\dfrac{y}{\left(x-1\right)+\dfrac{4}{15}}\end{matrix}\right.\)
102. Giải phương trình:
\(\left(x^2-2\right)\left(x^2+x+1\right)=0\)
giải phương trình
\(\left(x+5\right)^4+\left(x-4\right)^4=\left(2x+1\right)^4\)
\(\left(x-4\right)^4+\left(x-2\right)^4=81\)
PHÂN TÍCH:
a)\(\left(x^2+8x+12\right)\left(x^2+12x+32\right)+16\)
b)\(\left(x^2+6x+8\right)\left(x^2+8x+15\right)-24\)
c)\(\left(x^2-6x+5\right)\left(x^2-10x+21\right)-20\)
d)\(\left(x^2+x-2\right)\left(x^2+9x+18\right)-28\)
e)\(\left(x^2-11x+28\right)\left(x^2-7x+10\right)-72\)
f) \(\left(x^2+5x+6\right)\left(x^2-15x+56\right)-144\)
g)\(\left(x^2-x\right)^2+3\left(x^2-x\right)+2\)
h)\(\left(x^2+5x\right)^2+10x^2+50x+24\)
i)\(x^4+2016x^2+2015x+2016\)
Tính
\(A=\dfrac{1}{x\left(x+1\right)}+\dfrac{1}{\left(x+1\right)\left(x+2\right)}+\dfrac{1}{\left(x+2\right)\left(x+3\right)}+...+\dfrac{1}{\left(x+9\right)\left(x+10\right)}\)
Tìm \(x\)
a) \(\left(8-5x\right)\left(x+2\right)+4\left(x-2\right)\left(x+1\right)+2\left(x-2\right)\left(x+2\right)=0\)
b) \(\left(8x-3\right)\left(3x+2\right)-\left(4x+7\right)\left(x+4\right)=\left(2x+1\right)\left(5x-1\right)-33\)
