Tìm x, biết:
x^10-x^8=0
tìm x biết:x-10/30+x-5/95=14-x/43+148-x/8
\(...\Rightarrow x+x+\dfrac{x}{43}+\dfrac{x}{8}=14+148+\dfrac{10}{30}+\dfrac{5}{95}\)
\(\Rightarrow\left(1+1+\dfrac{1}{43}+\dfrac{1}{8}\right)x=162+\dfrac{1}{3}+\dfrac{1}{19}\)
\(\Rightarrow\left(\dfrac{2.43.8}{43.8}+\dfrac{1.8}{43.8}+\dfrac{1.43}{43.8}\right)x=\dfrac{162.3.19}{3.19}+\dfrac{1.19}{3.19}+\dfrac{1.3}{19.3}\)
\(\Rightarrow\left(\dfrac{688}{344}+\dfrac{8}{344}+\dfrac{43}{344}\right)x=\dfrac{9234}{57}+\dfrac{19}{57}+\dfrac{3}{57}\)
\(\Rightarrow\dfrac{739}{344}x=\dfrac{9256}{57}\)
\(\Rightarrow x=\dfrac{9256}{57}:\dfrac{739}{344}=\dfrac{9256}{57}.\dfrac{344}{739}=\dfrac{\text{3184064}}{\text{42123}}\)
tìm x biết:x^2+2x-10=0 mình cần gấp ah
\(x^2+2x-10=0\)
\(\Leftrightarrow x^2+2x+1-9=0\)
\(\Leftrightarrow\left(x+1\right)^2-9=0\\\)
\(\Leftrightarrow\left(x+1\right)^2=9\)
\(\Leftrightarrow\left(x+1\right)^2=\pm\sqrt{9}\)
\(\Leftrightarrow\left(x+1\right)^2=\left(\pm3\right)^2\)
\(\Leftrightarrow\left[{}\begin{matrix}x+1=3\\x+1=-3\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3-1\\x=-3-1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-4\end{matrix}\right.\)
Vậy S={2;-4}
\(x^2\) + 2\(x\) - 10 = 0
\(x^2\) + 2\(x\) + 1 - 11 = 0
(\(x^2\) + 2\(x\) + 1) - 11 = 0
(\(x\) + 1)2 - 11 = 0
(\(x\) + 1)2 = 11
\(\left[{}\begin{matrix}x+1=\sqrt{11}\\x+1=-\sqrt{11}\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=\sqrt{11}-1\\x=-\sqrt{11}-1\end{matrix}\right.\)
Tìm x,biết:
x(x+1)-(x-1)(x+2)=8
x(x+1)-(x-1)(x+2)=8
\(\Leftrightarrow\)\(x^2+x-x^2-2x+x+2=8\)
\(\Leftrightarrow0x=6\left(ptvn\right)\)
\(\Rightarrow S=\varnothing\)
Tìm xϵZ biết:
x-{[-x+(x+3)]} - [(x+3)-(x-2)]=0
\(\Rightarrow x-\left(-x+x+3\right)-\left(x+3-x+2\right)=0\\ \Rightarrow x-3-5=0\\ \Rightarrow x=8\)
Sai rồi bạn ơi, bằng -2 mới đúng,bn thử lại coi
tìm x biết:x^3-x=0
\(x^3-x=0\Rightarrow x\left(x^2-1\right)=0\)
TH1: \(x=0\)
TH2: \(x^2-1=0\Rightarrow x^2=1\Rightarrow x=\sqrt{1}\)hoặc \(x=-\sqrt{1}\)
Tìm số tự nhiên n biết:x+20 chia hết cho 10;x-15 chia hết cho 5;x chia hết cho 8 ;x+1 chia hết cho x (x bé hơn 300)
tìm [x] biết:
x- \(\dfrac{8}{5}\) < -6 < x
Ta có :
\(x-\dfrac{8}{5}< -6\\ \Rightarrow x< -6+\dfrac{8}{5}\\ \Rightarrow x< -\dfrac{22}{5}=-4\dfrac{2}{5}\\ \Rightarrow-6< x< -1\dfrac{2}{5}\\ \Rightarrow x=-5\)
Vậy...
Tìm [x], biết:
x - \(\dfrac{8}{5}\) < -6 < x
\(\Rightarrow\left\{{}\begin{matrix}x-\dfrac{8}{5}< -6\\-6< x\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x< -6+\dfrac{8}{5}\\x>-6\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x< -\dfrac{22}{5}\\x>-6\end{matrix}\right.\\ \Rightarrow-6< x< -\dfrac{22}{5}\)
Tìm số Z x, biết:
x . 2 - 5 . x = 0
tìm x biết:x+7/x=9(với x>0)
Lời giải:
$\frac{x+7}{x}=9$
$x+7=9\times x$
$7=9\times x-x$
$7=8\times x$
$x=7:8=\frac{7}{8}$