Tìm x: 116x^2 - x + 4= 0 Giúp mik với mik đag cần gấp
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\(2\cdot11^x=\left(3^2+2\right)^3:\left(5^3-2^5:2^3\right)\)
\(\Leftrightarrow11^x\cdot2=1331:121\)
\(\Leftrightarrow11^x\cdot2=11\)
=> Phương trình vô nghiệm
\(-x-2=\frac{5}{4}\)
\(\Rightarrow-x=\frac{5}{4}+2=\frac{13}{4}\)
\(\Rightarrow x=\frac{-13}{4}\)
\(-x-2=\frac{5}{4}\)
\(-x=\frac{5}{4}+2\)
\(-x=\frac{13}{4}\)
\(x=-\frac{13}{4}\)
\(2x\left(x-4\right)-6x^2\left(4-x\right)=0\)
\(\Leftrightarrow6x^2\left(x-4\right)+2x\left(x-4\right)=0\)
\(\Leftrightarrow2x\left(x-4\right)\left(3x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=4\\x=-\dfrac{1}{3}\end{matrix}\right.\)
\(2xy-x-y=2\\ \Rightarrow x\left(2y-1\right)-y=2\\ \Rightarrow2x\left(2y-1\right)-2y+1=4+1\\ \Rightarrow2x\left(2y-1\right)-\left(2y-1\right)=5\\ \Rightarrow\left(2x-1\right)\left(2y-1\right)=5\)
Ta có bảng:
2x-1 | -5 | -1 | 1 | 5 |
2y-1 | -1 | -5 | 5 | 1 |
x | -2 | 0 | 1 | 3 |
y | 0 | -2 | 3 | 1 |
Vậy \(\left(x,y\right)\in\left\{\left(-2;0\right);\left(0;-2\right);\left(1;3\right);\left(3;1\right)\right\}\)
\(2x^2+5x-3=0\)
\(\Leftrightarrow2x^2-x+6x-3=0\)
\(\Leftrightarrow x\left(2x-1\right)+3\left(2x-1\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(2x-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x+3=0\\2x-1=0\end{cases}\Rightarrow\orbr{\begin{cases}x=-3\\x=\frac{1}{2}\end{cases}}}\)
\(\dfrac{x}{15}\)+\(\dfrac{x}{12}\)=4/1+1/2=9/2
=>x(\(\dfrac{1}{15}\)+\(\dfrac{1}{12}\))=9/2
=>x\(\cdot\)\(\dfrac{3}{20}\)=9/2
=>x=9/2:3/20=30
Vậy x=30
\(\dfrac{x}{15}+\dfrac{x}{12}=\dfrac{9}{2}\Rightarrow\left(\dfrac{1}{15}+\dfrac{1}{12}\right)x=\dfrac{9}{2}\)
\(\Rightarrow\left(\dfrac{12+18}{180}\right)x=\dfrac{9}{2}\Rightarrow\dfrac{30}{180}x=\dfrac{9}{2}\Rightarrow\dfrac{1}{6}x=\dfrac{9}{2}\Rightarrow x=\dfrac{9}{2}.6=27\)
115x ² + x ² -x + 1/4 + 15/4 = (x-1/2) ² +115x ² + 15/4 ≥ 15/4
⇒ pt vô nghiệm