tìm x biết
(x-3)2-(x+3)2=24
Tìm x, biết: a) x = 1/4 + 5/13 b) x/3 = 2/3 + -1/7 c) x/3 = 16/24 + 24/ 36
d) x/15 = 1/5 + 2/3
\(a)x=\dfrac{1}{4}+\dfrac{5}{13}=\dfrac{33}{52}.\\ b)\dfrac{x}{3}=\dfrac{2}{3}+\dfrac{-1}{7}.\\ \Leftrightarrow\dfrac{x}{3}=\dfrac{11}{21}.\\ \Leftrightarrow\dfrac{7x}{21}=\dfrac{11}{21}.\\ \Rightarrow7x=11.\\ \Leftrightarrow x=\dfrac{11}{7}.\\ c)\dfrac{x}{3}=\dfrac{16}{24}+\dfrac{24}{36}=\dfrac{2}{3}+\dfrac{2}{3}=\dfrac{4}{3}.\\ \Rightarrow x=4.\\ d)\dfrac{x}{15}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{13}{15}.\\ \Rightarrow x=13.\)
Tìm x biết: a) \(\dfrac{6}{-x}=\dfrac{x}{-24}\) b) \(x-\dfrac{7}{12}x+\dfrac{3}{8}x=\dfrac{5}{24}\)
c)\(\left(x-\dfrac{1}{3}\right)^2-\dfrac{1}{2}=1\dfrac{3}{4}\) d) \(\dfrac{x-3}{-2}=\dfrac{-8}{x-3}\)
e) \(\dfrac{9}{x}=\dfrac{-35}{105}\) f) \(\left(x-\dfrac{1}{2}\right)\left(-3-\dfrac{x}{2}\right)=0\)
a: =>6/x=x/24
=>x^2=144
=>x=12 hoặc x=-12
b: =>x(1-7/12+3/8)=5/24
=>x*19/24=5/24
=>x=5/24:19/24=5/19
c: =>(x-1/3)^2=1+3/4+1/2=9/4
=>x-1/3=3/2 hoặc x-1/3=-3/2
=>x=11/6 hoặc x=-7/6
d: =>(x-3)^2=16
=>x-3=4 hoặc x-3=-4
=>x=-1 hoặc x=7
e: =>9/x=-1/3
=>x=-27
f: =>x-1/2=0 hoặc -x/2-3=0
=>x=1/2 hoặc x=-6
tìm x biết
(x-3)2-(x+3)2=24
Ta có:\(\left(x-3\right)^2-\left(x+3\right)^2=\left(x-3-x-3\right)\left(x-3+x+3\right)=-12x=24\)
\(\Rightarrow x=24\div\left(-12\right)=-2\)
Vậy x=-2
tào lao
(x-3)2bắt buộc phải nhỏ hơn (x+3)2mà (x-3)2-(x+3)2=24
xin thưa huynh van duong đó là đề cương trường mk đó
Tìm x,biết .3x+2-3x=24
Trả louwf ;.....................
x = 1.......................
Hk tốt.........................
tìm x biết : 3x+2-3x=24
3x+2-3x=24
3x.32-3x=24
3x.(32-1)=24
3x.(9-1)=24
3x.8=24
3x=24:8
3x=3
x=1
vậy x=1
3x+2 - 3 = 24
3x x 32 - 3 x = 24
3x x ( 9 -1) =24
3x x 8 = 24
3x = 24 : 8
3x = 3
suy ra x = 3
Vậy x =3
\(3^{x+2}-3^x=24\)
\(\Rightarrow3^x.\left(3^2-1\right)=24\)
\(\Rightarrow3^x.8=24\)
\(\Rightarrow3^x=3\)
\(\Rightarrow x=1\)
Tìm x biết
4(2x+7) - 3(3x - 2)=24
-2(x+3)+(-4)^2=3(1-x)
a) 4(2x+7)-3(3x-2)=24
8x+28-9x-6=24
(8x-9x)+(28-6)=24
(-1)x+22=24
(-1)x=24-22=2
x=2:(-1)=-2
b) -2(x+3)+(-4)2=3(1-x)
(-2)x+(-6)+16=3-3x
(-2)x+(-6)+16+3x=3
[(-2)x+3x]+[(-6)+16]=3
x+10=3
x=3-10=-7
Tìm x biết:
3.(x-2) - 60 = 24
Tìm x biết : x( x + 1 )( x + 2 )( x + 3 ) = 24
\(\Rightarrow x\left(x+3\right)\left(x+1\right)\left(x+2\right)=24\)
\(\Rightarrow\left(x^2+3x\right)\left(x^2+3x+2\right)=24\)
Đặt \(x^2+3x+1=t\)
\(\Rightarrow\left(t-1\right)\left(t+1\right)=24\)
\(\Rightarrow t^2-1=24\Rightarrow t^2=25\Rightarrow t=5;-5\)
Xét t=5 thì \(x^2+3x+1=5\Rightarrow x^2+3x-4=0\)
\(\Rightarrow x^2-x+4x-4=0\)
\(\Rightarrow x\left(x-1\right)+4\left(x-1\right)=0\)
\(\Rightarrow\left(x+4\right)\left(x-1\right)=0\Rightarrow x=-4;1\)
Xét t=-5 ta có
\(x^2+3x+1=-5\Rightarrow x^2+3x+6=0\)
\(\Rightarrow x_1=\frac{-3+\sqrt{15}i}{2};x_2=\frac{-3-\sqrt{15}i}{2}\)
mà \(x\in Z\)nên x=-4;1
Tìm x biết: (x-3)^2-16=0
x^2 -2x=24
(2x+1)+(x+3)^2(x+7)(x-7)=0
x^2 -2x = 24
=> x^2 - 2x - 24=0
=>x^2 -8x+6x - 24 = 0
=> ( x^2- 8x)+( 6x-24) = 0
=> x(x-8) + 6(x-8) = 0
=> (x+6)(x-8)=0
=>\(\orbr{\begin{cases}x=-6\\x=8\end{cases}}\)
\(=\frac{\left(2.5\right)^4.3^4-2^4\left(3.5\right)^2}{2^8.5^2.3^3}=\frac{2^4.3^2.5^2\left(5^2.3^2-1\right)}{2^8.5^2.3^3}=\frac{255-1}{16.3}=\frac{14}{3}\)
tìm x biết 5x(x-2)-3(x-1)=20x^2-15x(2x+1)-24
\(5x\left(x-2\right)-3\left(x-1\right)=20x^2-15x\left(2x+1\right)-24\)
\(\Rightarrow5x^2-10x-3x+3=20x^2-30x^2-15x-24\)
\(\Rightarrow5x^2-13x+3=-10x^2-15x-24\)
\(\Rightarrow5x^2+10x^2-13x+15x+3+24=0\)
\(\Rightarrow15x^2+2x+27=0\)
Ta có:
\(\Delta=2^2-4\cdot15\cdot27==-1616< 0\)
Nên pt vô nghiệm
\(5x\left(x-2\right)-3\left(x-1\right)=20x^2-15x\left(2x+1\right)-24\\ \Leftrightarrow5x^2-10x-3x+3=20x^2-30x^2-15x-24\\ \Leftrightarrow5x^2-20x^2+30x^2-10x-3x+15x+3+24=0\\ \Leftrightarrow15x^2+2x+27=0\\ \Leftrightarrow15x^2-2.x.\sqrt{15}+\dfrac{2}{15}+\dfrac{403}{15}=0\\ \Leftrightarrow\left(\sqrt{15}x+\dfrac{\sqrt{30}}{15}\right)^2+\dfrac{403}{15}=0\left(Vô.lí\right)\\ Vậy:Không.có.x.thoả\)