2x+2 - 2x = 48
2 x - 2 - 2 x + 1 . x 2 + 4 x + 4 8
CÍU EM VS !
Tìm x:
2^2x + 2^2x+1 = 48
\(2^{2x}+2^{2x+1}=48\)
\(2^{2x}+2^{2x}.2=48\)
\(2^{2x}.\left(1+2\right)=48\)
\(2^{2x}.3=48\)
\(2^{2x}=48:3\)
\(2^{2x}=16\)
\(2^{2x}=2^4\)
\(\Rightarrow2x=4\)
\(x=4:2\)
\(x=2\)
\(2^{2x}+2^{2x+1}=48\\ \Rightarrow2^{2x}+2.2^{2x}=48\\ \Rightarrow\left(1+2\right).2^{2x}=48\\ \Leftrightarrow3.2^{2x}=48\\ \Leftrightarrow2^{2x}=16\\ \Leftrightarrow2^{2x}=2^4\\ \Leftrightarrow2x=4\\ \Leftrightarrow x=2\)
Vậy x = 2
Tìm x, biết:
4 * 2^x42 - 2x = 480
(2x^2 + 1)*(x-3)=0
48-(15-x)^5=48
(2x2 + 1)(x-3)=0
\(\Rightarrow\orbr{\begin{cases}2x^2+1=0\\x-3=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}2x^2=-1\Rightarrow x^2=-\frac{1}{2}\left(vl\right)\\x=3\end{cases}}\)
Vậy x=3
48-(15-x)5=48
(15-x)5=48-48
(15-x)5=0
=> 15-x =0
x =15-0
x =15
Vậy x=15
Tìm x:
a) x(2-x)+(x2+x)=7
b) (2x+1)2-x(4-5x)=17
c) (4-x)2-(2x+1)2=0
d) (2x3-8x2+10x) : (2x)=0
e) (4x4-16x-48) : (-2x)2=0
a: Ta có: \(x\left(2-x\right)+\left(x^2+x\right)=7\)
\(\Leftrightarrow2x-x^2+x^2+x=7\)
\(\Leftrightarrow3x=7\)
hay \(x=\dfrac{7}{3}\)
b: Ta có: \(\left(2x+1\right)^2-x\left(4-5x\right)=17\)
\(\Leftrightarrow4x^2+4x+1-4x+5x^2=17\)
\(\Leftrightarrow9x^2=16\)
\(\Leftrightarrow x^2=\dfrac{16}{9}\)
hay \(x\in\left\{\dfrac{4}{3};-\dfrac{4}{3}\right\}\)
c: Ta có: \(\left(x-4\right)^2-\left(2x+1\right)^2=0\)
\(\Leftrightarrow\left(x-4-2x-1\right)\left(x-4+2x+1\right)=0\)
\(\Leftrightarrow\left(x+5\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=1\end{matrix}\right.\)
d: ta có: \(\dfrac{2x^3-8x^2+10x}{2x}=0\)
\(\Leftrightarrow x^2-4x+5=0\)
\(\Leftrightarrow\left(x-2\right)^2+1=0\)(vô lý)
Tìm x:
a) x(2-x)+(x2+x)=7
b) (4-x)2-(2x+1)2=0
c) (4x4-16x-48) : (-2x)2=0
a: Ta có: \(x\left(2-x\right)+x^2+x=7\)
\(\Leftrightarrow2x-x^2+x^2+x=7\)
\(\Leftrightarrow3x=7\)
hay \(x=\dfrac{7}{3}\)
b: Ta có: \(\left(x-4\right)^2-\left(2x+1\right)^2=0\)
\(\Leftrightarrow\left(x-4-2x-1\right)\left(x-4+2x+1\right)=0\)
\(\Leftrightarrow\left(x+5\right)\left(3x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=1\end{matrix}\right.\)
tìm x.y là stn a) (2x-1)(5y+1) = 30 b) (2x + 1)(y-2)=48
1) x^2 + x - 6
2) x^2 - x - 6
3) x^2 + 2x - 48
4) x^2 - 2x -48
5) x^2 + x- 42
6) x^2 - x-42
1) \(x^2+x-6=x\left(x-2\right)+3\left(x-2\right)=\left(x+3\right)\left(x-2\right)\)
2) \(x^2-x-6=\left(x-3\right)\left(x+2\right)\)
3) \(x^2+2x-48=\left(x-6\right)\left(x+8\right)\)
4) \(x^2-2x-48=\left(x-8\right)\left(x+6\right)\)
5) \(x^2+x-42=\left(x-6\right)\left(x+7\right)\)
6) \(x^2-x-42=\left(x-7\right)\left(x+6\right).\)
1) \(x^2+x-6\)
\(=x^2-2x+3x-6\)
\(=\left(x^2-2x\right)+\left(3x-6\right)\)
\(=x\left(x-2\right)+3\left(x-2\right)\)
\(=\left(x-2\right)\left(x+3\right)\)
2) \(x^2-x-6\)
\(=x^2+2x-3x-6\)
\(=\left(x^2+2x\right)-\left(3x+6\right)\)
\(=x\left(x+2\right)-3\left(x+2\right)\)
\(=\left(x+2\right)\left(x-3\right)\)
3) \(x^2+2x-48\)
\(=x^2+8x-6x-48\)
\(=\left(x^2+8x\right)-\left(6x+48\right)\)
\(=x\left(x+8\right)-6\left(x+8\right)\)
\(=\left(x+8\right)\left(x-6\right)\)
4) \(x^2-2x-48\)
\(=x^2-8x+6x-48\)
\(=\left(x^2-8x\right)+\left(6x-48\right)\)
\(=x\left(x-8\right)+6\left(x-8\right)\)
\(=\left(x-8\right)\left(x+6\right)\)
5) \(x^2+x-42\)
\(=x^2+7x-6x-42\)
\(=\left(x^2+7x\right)-\left(6x+42\right)\)
\(=x\left(x+7\right)-6\left(x+7\right)\)
\(=\left(x+7\right)\left(x-6\right)\)
6) \(x^2-x-42\)
\(=x^2-7x+6x-42\)
\(=\left(x^2-7x\right)+\left(6x-42\right)\)
\(=x\left(x-7\right)+6\left(x-7\right)\)
\(=\left(x-7\right)\left(x+6\right)\)
tìm x,y,z biết
6) x=3y=2z và 2x-3y+4z=48
7) 2x=3y=-2z và 2x-3y+4z=48
\(x=3y=2z\)
\(\Rightarrow\frac{x}{1}=\frac{y}{2}=\frac{z}{3}\)
\(\Rightarrow\frac{2x}{2}=\frac{3y}{6}=\frac{4z}{12}=\frac{2x-3y+4z}{2-6+12}=\frac{48}{8}=6\)
Rồi thế vào là ra thôi :
\(\frac{2x}{2}=6\Rightarrow x=..........\)
Rồi tương tự thôi
tìm x,y,z biết
6) x=3y=2z và 2x-3y+4z=48
7) 2x=3y=-2z và 2x-3y+4z=48
6)
\(x=3y=2z\)
\(\Rightarrow\frac{x}{6}=\frac{y}{2}=\frac{z}{3}\)
\(\Rightarrow\frac{2x}{12}=\frac{3y}{6}=\frac{4z}{12}\)
Áp dụng tc của dãy tỉ số bằng nhau ta có
\(\frac{2x}{12}=\frac{3y}{6}=\frac{4z}{12}=\frac{2x-3y+4z}{12-6+12}=\frac{48}{18}=\frac{24}{9}\)
\(\Rightarrow\begin{cases}x=16\\y=\frac{16}{3}\\z=8\end{cases}\)
7)
\(2x=3y=-2z\)
\(\Rightarrow\frac{2x}{1}=\frac{3y}{1}=\frac{-4z}{2}\)
Áp dụng tc của dãy tỉ số bằng nhau ta có
\(\frac{2x}{1}=\frac{3y}{1}=\frac{-4z}{2}=\frac{2x-3y-\left(-4z\right)}{1-1-2}=\frac{48}{-2}=-24\)
\(\Rightarrow\begin{cases}x=-12\\y=-8\\z=12\end{cases}\)
6) *2x - 3y + 4z = 48
<=> 4z -2z +4z = 48
=> ( 4-2+4)z = 48
=> z=8 => 2z= 16
* 2x -3y + 4z =48
<=> 6y - 3y +6y =48
=> (6 - 3+ 6)y = 48
=> y= \(\frac{16}{3}\) => 3y = 16
* 2x - 3y + 4z =48
<=> 2x -x + 2x = 48
=> ( 2 -1 +2)x =48
=>x= 16
2x^3 + 3X^2 - 32x =48
Ta có: 2x3 + 3x2 - 32x =48
<=> 2x3 + 3x2 - 32x - 48 =0
<=> x2(2x+3) - 16(2x+3) =0
<=> (x2-16)(2x+3) =0
<=> (x-4)(x+4)(2x+3) =0
<=> x-4=0 hoặc x+4=0 hoặc 2x+3=0
<=> x=4 hoặc x=-4 hoặc x= \(\dfrac{-3}{2}\)
Vậy phương trình trên có tập nghiệm là S={4;-4;\(\dfrac{-3}{2}\)}
2x3+3x2-32x=48
⇔2x3+3x2-32x-48=0
⇔x2(2x+3)-16(2x+3)=0
⇔(2x+3)(x2-16)=0
⇔(2x+3)(x-4)(x+4)=0
⇔2x+3=0 hoặc x-4=0 hoặc x+4=0
1.2x+3=0⇔2x=-3⇔x=-3/2
2.x-4=0⇔x=4
3.x+4=0⇔x=-4
phương trình có 3 nghiệm:x=-3/2 và x=4 và x=-4
Ta có: \(2x^3+3x^2-32x=48\)
\(\Leftrightarrow2x^3+3x^2-32x-48=0\)
\(\Leftrightarrow x^2\left(2x+3\right)-16\left(2x+3\right)=0\)
\(\Leftrightarrow\left(2x+3\right)\left(x^2-16\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+3=0\\x^2-16=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=-3\\x^2=16\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=4\\x=-4\end{matrix}\right.\)
vậy: \(S=\left\{-\dfrac{3}{2};4;-4\right\}\)