\(\left(3x-2\right)\left(4x-5\right)-\left(2x-1\right)\left(6x+2\right)=0\)
\(\Leftrightarrow12x^2-15x-8x+10-\left(12x^2+4x-6x-2\right)=0\)
\(\Leftrightarrow12x^2-15x-8x+10-12x^2-4x+6x+2=0\)
\(\Leftrightarrow-21x+12=0\Leftrightarrow21x=12\Leftrightarrow x=\dfrac{12}{21}=\dfrac{4}{7}\)
vậy \(x=\dfrac{4}{7}\)
Tìm x :
\(\left(2x^2+1\right)\cdot\left(3x^2-1\right)-\left(4x^2-3\right)\cdot\left(x^2+1\right)=x\cdot\left(2x^2+1\right)\)
\(\left(3x-1\right)\cdot\left(2x+7\right)-\left(x+1\right)\cdot\left(6x-5\right)=16\)
XÁT ĐỊNH a,b,c BIẾT RẰNG:
a/\(-4x^{^{ }3}\cdot\left(ax^2+bx+c\right)=-8x^5+12x^4-20x^3\)
b/\(-2x^3\cdot\left(ax^2-bx-c\right)=-4x^5+6x^4+2x^3\)
Tìm \(x\) , biết:
a) \(\left(x+2\right)\left(x+3\right)-\left(x-2\right)\left(x+5\right)=6\)
b) \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
c) \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)
CÁC BẠN LÀM NHANH GIÚP MIK NHA!
Tìm x, biết
a) \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
b) \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)
Tìm x biết : (đề không sai)
1.\(-4x\left(x-7\right)+4x\left(x^2-5\right)\) \(=28x^2-13\)
2.\(\left(4x^2-5x\right)\left(3x+2\right)-7x\left(x-7\right)\)= \(\left(-4+x\right)\left(-2x+3\right)+12x^3+2x^2\)
3.\(\left(-4x^2-3\right)\left(2x+5\right)-\left(8x-3\right)\) \(\left(-x^2+2\right)=-5x^2\left(x-6\right)-3x^2-4\)
4.\(\left(x-7\right)\left(x+5\right)-\left(x-3\right)\left(x-2\right)\) \(=15x^2\left(x+1\right)-\left(3x^2-1\right)\) \(\left(5x^2-2\right)-21x^2\)
5.\(\left(x-3\right)\left(-x+10\right)+\left(x-8\right)\left(x+3\right)\) \(=\left(5x^2-1\right)\left(x+3\right)-5x^3-15x^2\)
6.\(\left(-2x^2+5\right)\left(-x+3\right)-x^2\left(2x-6\right)\) \(=\left(x-1\right)\left(x+1\right)-\left(x-2\right)\left(x+4\right)\)
Chứng minh đẳng thức sau :
\(x.\left(x+1\right)\cdot\left(x+2\right)=x^3+3x^2+2x\)
tìm x, biết:
\(a,-4x\left(x-7\right)+4x\left(x^2-5\right)=28x^2-13\)
\(b,\left(4x^2-5x\right)\left(3x+2\right)-7x\left(x+5\right)\) \(=\left(-4+x\right)\left(-2x+3\right)+12x^2+2x^2\)
Tìm x:
a.\(5x-3\left\{4x-2\left[4x-3(5x-2)\right]\right\}=182\)
b.\(\left(x+2\right)\left(x+3\right)-\left(x-2\right)\left(x+5\right)=0\)
c.\(\left(2x+3\right)\left(x-4\right)+\left(x-5\right)\left(x-2\right)=\left(3x-5\right)\left(x-4\right)\)
Giúp mk vs!!