Tìm x biết
A/3x^2-3x(x-2)=36
B/(3x^2-x+1)(x-1)+x^2(4-3x)=5/2
Giải giúp với
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\(a,3x^2-3x\left(x-2\right)=36\\ \Leftrightarrow3x^2-3x^2+6x=36\\ \Leftrightarrow6x=36\\ \Leftrightarrow x=6\\ b,5x\left(4x^2-2x+1\right)-2x\left(10x^2-5x+2\right)=-36\\ \Leftrightarrow20x^3-10x^2+5x-20x^3+10x^2-4x+36=0\\ \Leftrightarrow\left(20x^3-20x^3\right)+\left(-10x^2+10x^2\right)+\left(5x-4x\right)=-36\\ \Leftrightarrow x=-36\)
1: \(\left(2x-2\right)\left(3x+1\right)-\left(3x-2\right)\left(2x-3\right)=5\)
=>\(6x^2+2x-6x-2-\left(6x^2-9x-4x+6\right)=5\)
=>\(6x^2-4x-2-6x^2+13x-6=5\)
=>9x-8=5
=>9x=13
=>\(x=\frac{13}{9}\)
2: \(\left(1-3x\right)\left(3x-5\right)-\left(2x-4\right)\left(2-3x\right)=x-6\)
=>\(3x-5-9x^2+15x+\left(2x-4\right)\left(3x-2\right)=x-6\)
=>\(-9x^2+18x-5+6x^2-4x-12x+8=x-6\)
=>\(-3x^2+2x+3-x+6=0\)
=>\(-3x^2+x+9=0\)
=>\(3x^2-x-9=0\)
=>\(x^2-\frac13x-3=0\)
=>\(x^2-2\cdot x\cdot\frac16+\frac{1}{36}-\frac{109}{36}=0\)
=>\(\left(x-\frac16\right)^2=\frac{109}{36}\)
=>\(x-\frac16=\pm\frac{\sqrt{109}}{6}\)
=>\(x=\frac16\pm\frac{\sqrt{109}}{6}\)
3: \(\left(2x-1\right)\left(4x^2+2x+1\right)-\left(2x+1\right)\left(4x^2-2x+1\right)=5x+6\)
=>\(8x^3-1-8x^3-1=5x+6\)
=>5x+6=-2
=>5x=-8
=>\(x=-\frac85\)
\(a,\Rightarrow12x-91=101\\ \Rightarrow12x=192\\ \Rightarrow x=16\\ b,\Rightarrow x:23+45=133\\ \Rightarrow x:23=88\\ \Rightarrow x=\dfrac{88}{23}\\ c,\Rightarrow\left(6x-39\right):7=3\\ \Rightarrow6x-39=21\\ \Rightarrow6x=60\\ \Rightarrow x=10\\ d,\Rightarrow3x-24=\dfrac{148}{73}\\ \Rightarrow3x=\dfrac{1900}{73}\\ \Rightarrow x=\dfrac{1900}{219}\\ e,\Rightarrow\left[{}\begin{matrix}x=0\\x=10\end{matrix}\right.\\ f,\Rightarrow\left[{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\\ d,\left(9-x\right)^3=64=4^3\\ \Rightarrow9-x=4\\ \Rightarrow x=5\\ h,\Rightarrow x=27\\ i,\Rightarrow6x=312\cdot12=624\cdot6\\ \Rightarrow x=624\\ j,\Rightarrow\left(19x+104\right):14=25-42=-17\\ \Rightarrow19x+104=-238\\ \Rightarrow19x=-342\\ \Rightarrow x=-18\)
a: \(A=-18x^3y^4z\)
Bậc là 8
b: \(M=3x^2+3xy-x^3-3x^2-2xy+4y^2=-x^3+xy+4y^2\)
a) (x-2)3+6(x+1)2-x3+12=0
\(\Rightarrow\)x3-6x2+12x-8+6(x2+2x+1)-x3+12=0
\(\Rightarrow\)x3-6x2+12x-8+6x2+12x+6-x3+12=0
\(\Rightarrow\)24x+10=0
\(\Rightarrow\)24x=-10
\(\Rightarrow\)x=\(\dfrac{-10}{24}=\dfrac{-5}{12}\)
b)(x-5)(x+5)-(x+3)2+3(x-2)2=(x+1)2-(x-4)(x+4)+3x2
\(\Rightarrow\)x2-25-(x2+6x+9)+3(x2-4x+4)=x2+2x+1-(x2-16)+3x2
\(\Rightarrow\)x2-25-x2-6x-9+3x2-12x+12=x2+2x+1-x2+16+3x2
\(\Rightarrow\)3x2-18x-22=3x2+2x+17
\(\Rightarrow\)3x2-18x-22-3x2-2x-17=0
\(\Rightarrow\)-20x-39=0
\(\Rightarrow\)-20x=39
\(\Rightarrow\)x=\(-\dfrac{39}{20}\)