Giải pt sau: x/24+x-6/32=2x-6/27
Giải pt:27= 6\(\sqrt{x+8}\) + x+4\(\sqrt{6-2x}\)
ĐKXĐ: \(\left\{{}\begin{matrix}x+8>=0\\6-2x>=0\end{matrix}\right.\Leftrightarrow-8< =x< =3\)
\(PT\Leftrightarrow1=6\sqrt{x+8}-18+x+4\sqrt{6-2x}-8\)
\(\Leftrightarrow6\cdot\dfrac{x+8-9}{\sqrt{x+8}+3}+x-1+4\cdot\dfrac{6-2x-4}{\sqrt{6-2x}+2}=0\)
=>\(\left(x-1\right)\left(\dfrac{6}{\sqrt{x+8}+3}+1-\dfrac{4}{\sqrt{6-2x}+2}\right)=0\)
=>x-1=0
=>x=1
Giải các pt sau: a,(x2+5x+6)(x2+9x+20)=24
b,x4-24x=32
(x2 + 5x + 6)(x2 + 9x + 20) = 24
<=> (x + 2)(x + 3)(x + 4)(x + 5) - 24 = 0
<=> (x2 + 7x + 10)(x2 + 7x + 12) - 24 = 0 (1)
Đặt x2 + 7x + 11 = t, ta có:
(1) <=> (t - 1)(t + 1) - 24 = 0
<=> t2 - 1 - 24 = 0
<=> (t - 5)(t + 5) = 0
\(\Leftrightarrow\left[{}\begin{matrix}t-5=0\\t+5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x^2+7x+11-5=0\\x^2+7x+11+5=0\end{matrix}\right.\)
<=> (x + 1)(x + 6) = 0 (vì \(x^2+7x+16\ge\dfrac{15}{4}>0\))
<=> x = - 1 hoặc x = - 6
~ ~ ~ ~ ~
x4 - 24x = 32
<=> x4 - 24x - 32 = 0
<=> (x2 - 2x - 4)(x2 + 2x + 8) = 0
<=> \(\left(x-1-\sqrt{5}\right)\left(x-1+\sqrt{5}\right)=0\) (vì \(x^2+2x+8\ge7>0\))
\(\Leftrightarrow\left[{}\begin{matrix}x=1+\sqrt{5}\\x=1-\sqrt{5}\end{matrix}\right.\)
giải pt sau:
4+6/x= (24-(24*(x+21)*6)/(15*x+234))*(12+x)*(5/18+1/x)
Bài1: giải các pt sau:
a, 3-4x+24+6x= x+27+3x
b, 5-(6-x)=4(3-2x)
c, x-(x+1)/3 = (2x+1)/5
d,(2x-1)/3 - (5x+2)/7 = x+13
Bài 2:
a, (x-1)(3x+1)=0
b, (x-5)(7-x)=0
c, ( x-1)(x+5)(-3x+8)=0
d, x(x^2 - 1 )=0
Giúp mình 2 bài này với , mình đang cần gấp , CẢM ƠN M.N ạ><
2:
a: =>x-1=0 hoặc 3x+1=0
=>x=1 hoặc x=-1/3
b: =>x-5=0 hoặc 7-x=0
=>x=5 hoặc x=7
c: =>\(\left[{}\begin{matrix}x-1=0\\x+5=0\\3x-8=0\end{matrix}\right.\Leftrightarrow x\in\left\{1;-5;\dfrac{8}{3}\right\}\)
d: =>x=0 hoặc x^2-1=0
=>\(x\in\left\{0;1;-1\right\}\)
Giải pt: x2 + x + 24 - 2x\(\sqrt{2x+3}\) = 6\(\sqrt{12-x}\)
ĐKXĐ: \(-\frac{3}{2}\le x\le12\)
\(\Leftrightarrow x^2-2x\sqrt{2x+3}+2x+3+12-x-6\sqrt{12-x}+9=0\)
\(\Leftrightarrow\left(x-\sqrt{2x+3}\right)^2+\left(\sqrt{12-x}-3\right)^2=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-\sqrt{2x+3}=0\\\sqrt{12-x}-3=0\end{matrix}\right.\) \(\Rightarrow x=3\)
Bài 1:
a) Giải PT sau: \(\dfrac{x+1}{x-2}-\dfrac{5}{x+2}=\dfrac{12}{x^2-4}+1\)
b) Giải PT sau: |2x+6|-x=3
a) ĐKXĐ: \(x\notin\left\{2;-2\right\}\)
Ta có: \(\dfrac{x+1}{x-2}-\dfrac{5}{x+2}=\dfrac{12}{x^2-4}+1\)
\(\Leftrightarrow\dfrac{\left(x+1\right)\left(x+2\right)}{\left(x-2\right)\left(x+2\right)}-\dfrac{5\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}=\dfrac{12}{\left(x-2\right)\left(x+2\right)}+\dfrac{x^2-4}{\left(x-2\right)\left(x+2\right)}\)
Suy ra: \(x^2+3x+2-5x+10=12+x^2-4\)
\(\Leftrightarrow x^2-2x+12-8-x^2=0\)
\(\Leftrightarrow-2x+4=0\)
\(\Leftrightarrow-2x=-4\)
hay x=2(loại)
Vậy: \(S=\varnothing\)
b) Ta có: \(\left|2x+6\right|-x=3\)
\(\Leftrightarrow\left|2x+6\right|=x+3\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+6=x+3\left(x\ge-3\right)\\-2x-6=x+3\left(x< -3\right)\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-x=3-6\\-2x-x=3+6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-3\left(nhận\right)\\x=-3\left(loại\right)\end{matrix}\right.\)
Vậy: S={-3}
Giải PT sau
/x - 6/ = /3 - 2x/
=>x-6=3-2x hoặc x-6=2x-3
=>3x=9 hoặc -x=3
=>x=3 hoặc x=-3
\(\left|x-6\right|=\left|3-2x\right|\\ \Leftrightarrow\left[{}\begin{matrix}x-6=3-2x\\x-6=2x-3\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x-6-3+2x=0\\2x-3-x+6=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}3x-9=0\\x+3=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)
GIẢI CÁC PT SAU:
\(\sqrt{5x+10}=8-x\)
\(\sqrt{4x^2+x-12}=3x-5\)
\(\sqrt{x^2-2x+6}=2x-3\)
\(\sqrt{3x^2-2x+6}+3-2x=0\)
Giải pt bậc hai sau : x³ + 3x² = 2x - 6
<=> \(x^2\left(x+3\right)-2\left(x+3\right)=0\)
\(\Leftrightarrow\left(x^2+2\right)\left(x+3\right)=0\\ \Rightarrow\left\{{}\begin{matrix}x^2-2=0\\x+3=0\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}x=\pm\sqrt{2}\\x=-3\end{matrix}\right.\)