a)(x+3)3-x(3x+1)2+(2x+1)(4x2-2x+1-3x2)=54
\(\Rightarrow\)x3+9x2+27x+27-x(9x2+6x+1)+(2x+1)(x2-2x+1)=54
\(\Rightarrow\)x3+9x2+27x+27-9x3-6x2-x+2x3-4x2+2x+x2-2x+1=54
\(\Rightarrow\)-6x3+26x+28=54
\(\Rightarrow\)-6x3+26x=54-28
\(\Rightarrow\)-6x3+26x=26
\(\Rightarrow\)-6x3+26x-26=0
\(\Rightarrow\)-2(3x3+13x+14)
B1 ( kết quả thôi ko cần lời giải)
a) \(\left(4x-3\right)\left(3x+2\right)-\left(6x+1\right)\left(2x-5\right)+1\)
b) \(\left(3x+4\right)^2+\left(4x-1\right)^2+\left(2+5x\right)\left(2-5x\right)\)
c) \(\left(2x+1\right)\left(4x^2-2x+1\right)+\left(2-3x\right)\left(4+6x+9x^2\right)-9\)
B2 tìm x(kết quả)
a) \(3x\left(x-4\right)-x\left(5+3x\right)=-34\)
b) \(\left(3x+1\right)^2+\left(5x-2\right)^2=34\left(x+2\right)\left(x-2\right)\)
c) \(x^3+3x^2+3x+28=0\)
Tìm x
\(\left(x-3\right)^3-x.\left(3x+1\right)^2+\left(2x+1\right).\left(4x^2-2x+1-3x^2\right)\)
Tìm x: \(\left(3x-1\right)^3-2\left(2x-3\right)^2-3\left(x-2\right)\left(3-x\right)=\left(1+3x\right)^3-2\left(1+3x\right)^2\)
Tìm x: \(\left(2x-1\right)^3-3\left(3x+1\right)^2=\left(3+2x\right)^3-2\left(2-x\right)^2-\left(x-1\right)\left(x+2\right)\)
Tìm x : \(\left(2x-1\right)^3-3\left(1-3x\right)^2=\left(3+2x\right)^3-2\left(x-2\right)\left(x+3\right)\)
Tìm x : \(\frac{2\left(x-1\right)\left(x-3\right)}{3}-\frac{4\left(2x-1\right)^2}{5}=\frac{\left(1+3x\right)^2}{2}-3x\left(1-x\right)\)
Tìm x : \(\frac{2\left(x-1\right)\left(x-3\right)}{3}-\frac{4\left(2x-1\right)^2}{5}=\frac{\left(1+3x\right)^2}{2}-3x\left(1-x\right)\)
Tìm x : \(\left(x-2\right)^3+\left(3x-2\right)^2-5x\left(x+1\right)=\left(1+x\right)^3-2\left(2x+1\right)^2\)
Giải các PT sau:
a)\(2x\left(8x-1\right)^2\left(4x-1\right)=9\)
b)\(\left(12x+7\right)^2\left(3x+2\right)\left(2x+1\right)=3\)
c)\(\left(2x+1\right)\left(x+1\right)^2\left(2x+3\right)=18\)
