cần tìm X:
a. 3x+2.[-2]3=-[-2]3
b. 4x-15=-75-x
mn giúp mình
Tìm x:
a)\(\sqrt{3x-6}\)=3
b)\(\sqrt{5x-16}\)=2
c)Tìm điều kiện xác định của biểu thức: B=\(\dfrac{2x-3}{x^2-4x+3}\)
a) ĐK: x ≥ 2
\(\sqrt{3x-6}=3\)
\(\Leftrightarrow3x-6=9\)
<=> 3x = 15
<=> x = 5
Vậy:....
b) ĐK: 5x - 16 ≥ 0
<=> 5x ≥ 16
<=> x ≥ 16/5
\(\sqrt{5x-16}=2\)
<=> 5x - 16 = 4
<=> 5x = 20
<=> x = 4
c) ĐK: \(x^2-4x+3\ne0\)
\(\Leftrightarrow\left(x-1\right)\left(x-3\right)\ne0\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ne1\\x\ne3\end{matrix}\right.\)
bình phương hai vế ta được:
a)điều kiện của x:x≥2
3x-6=9 <=> x=5(nhận)
b)ĐK: x≥16/5
5x-16=4 <=>x=4(nhận)
c) ta có: \(\dfrac{2x-3}{\left(x-2\right)^2-1}\)= \(\dfrac{2x-3}{\left(x-3\right)\left(x-1\right)}\)
ĐKXĐ: x≠3 ;x≠1
a,\(\sqrt{3x-6}=3\) (với x\(\ge\)2)
=>\(\left(\sqrt{3x-6}\right)^2=3^2\)
<=>\(3x-6=9\)<=>\(3x=9+6\)<=>x=\(\dfrac{15}{3}\)=5(thỏa mãn)
b,\(\sqrt{5x-16}=2\) (với x\(\ge\)16/5)
=>\(\left(\sqrt{5x-16}\right)^2=2^2\)<=>\(5x-16=4< =>5x=20< =>x=4\)(thỏa mãn)
c,B xác định khi \(x^2-4x+3\ne0< =>x^2-2.2.x+2^2-1\ne0\)
\(< =>\left(x-2\right)^2-1\ne0\)
\(< =>\left(x-2+1\right)\left(x-2-1\right)\ne\)0
\(< =>\left(x-1\right)\left(x-3\right)\ne0\)
\(< =>\left[{}\begin{matrix}x-1\ne0\\x-3\ne0\end{matrix}\right.< =>\left[{}\begin{matrix}x\ne1\\x\ne3\end{matrix}\right.\)
tìm x:
a)3(2x-3)+2(2-x)=-3
b)2x(x2-2)+x2(1-2x)-x2=-12
c)3x(2x+3)-(2x+5)(3x-2)=8
d)4x(x - 1) - 3(x2-5)-x2=(x-3)-(x+4)
e)2(3x-1)(2x+5)-6(2x-1)(x+2)=-6
a: Ta có: \(3\left(2x-3\right)+2\left(2-x\right)=-3\)
\(\Leftrightarrow6x-9+4-2x=-3\)
\(\Leftrightarrow4x=2\)
hay \(x=\dfrac{1}{2}\)
tìm x:
3x+2.(-2)3=-(-2)3
4x-15=-75-x
MN ơi giúp mình nhanh
\(3x+2\left(-2\right)^3=-\left(-2\right)^3\)
\(\Leftrightarrow3x+2\cdot\left(-8\right)=-8\)
\(\Leftrightarrow3x-16=-8\)
\(\Leftrightarrow3x=8\)
\(\Leftrightarrow x=\frac{8}{3}\)
4x-15=-75-x
\(\Leftrightarrow4x+x=-75+15\)
\(\Leftrightarrow5x=-60\)
\(\Leftrightarrow x=-12\)
3x + 2. (-2)3 = -(-2)3
3x + 2. (-8) = -(-8)
3x + (-16) = 8
3x = 8 + 16
3x = 24
x = 24 : 3
x = 8
Vậy x = 8
4x - 15 = -75 - x
4x + x = -75 + 15
5x = -60
x = (-60) : 5
x = -12
Vậy x = -12
Chúc bạn học tốt!!!
Tìm x:
a) 36x3-4x=0
b) 3x(x-2)-2+x=0
c) (x3-x2)-4x2+8x-4=0
d) x2-6x-16=0
e) x4-6x2-7=0
(Mình cần gấp ạ)
a) Ta có: \(36x^3-4x=0\)
\(\Leftrightarrow4x\left(9x^2-1\right)=0\)
\(\Leftrightarrow x\left(3x-1\right)\left(3x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{1}{3}\\x=\dfrac{-1}{3}\end{matrix}\right.\)
b) Ta có: \(3x\left(x-2\right)+x-2=0\)
\(\Leftrightarrow\left(x-2\right)\left(3x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{-1}{3}\end{matrix}\right.\)
d) Ta có: \(x^2-6x-16=0\)
\(\Leftrightarrow\left(x-8\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=8\\x=-2\end{matrix}\right.\)
e) Ta có: \(x^4-6x^2-7=0\)
\(\Leftrightarrow\left(x^2-7\right)\left(x^2+1\right)=0\)
\(\Leftrightarrow x\in\left\{\sqrt{7};-\sqrt{7}\right\}\)
Tìm x:
a,| 4 + 2x| = -4x
b,|3x - 1|+ 2 = x
c, |x + 15 | + 1 = 3x
d,| 2x - 5| = x + 2
Tìm x:
a)x(x+4)+(5+x)(5-x)=3
b)(2x-3)^2=(4x+3)^2
mình cảm ơn
\(a,\Rightarrow x^2+4x+25-x^2=3\\ \Rightarrow4x=-22\Rightarrow x=-\dfrac{11}{2}\\ b,\Rightarrow\left(2x-3-4x-3\right)\left(2x-3+4x+3\right)=0\\ \Rightarrow6x\left(-2x-6\right)=0\Rightarrow\left[{}\begin{matrix}x=-3\\x=0\end{matrix}\right.\)
tìm x:
a,32:(3xX-2)=8
b,75:(X-18)=25
c,(15-6xX)x243=729
d,4x(X-12)+9=17
e,20-2x(X+4)=4
a) 32 : (3.x - 2) = 8
3x - 2 = 32 : 8
3x - 2 = 4
3x = 4 + 2
3x = 6
x = 6 : 3
x = 2
b) 75 : (x - 18) = 25
x - 18 = 75 : 25
x - 18 = 3
x = 3 + 18
x = 21
c) (15 - 6.x) . 243 = 729
15 - 6x = 729 : 243
15 - 6x = 3
6x = 15 - 3
6x = 12
x = 12 : 6
x = 2
d) 4.(x - 12) + 9 = 17
4(x - 12) = 17 - 9
4(x - 12) = 8
x - 12 = 8 : 4
x - 12 = 2
x = 2 + 12
x = 14
e) 20 - 2.(x + 4) = 4
2(x + 4) = 20 - 4
2(x + 4) = 16
x + 4 = 16 : 2
x + 4 = 8
x = 8 : 2
x = 4
`32: ( 3xx x -2)=8`
`3xx x-2=32:8`
`3xx x-2=4`
`3 xx x=4+2`
`3xx x=6`
`x=6:3`
`x=2`
__
`75 : (x-18) =25`
`x-18=75:25`
`x-18= 3`
`x=3+18`
`x=21`
__
`(15-6 xx x ) xx 243 =729`
`15-6 xx x = 729 : 243`
`15-6 xx x = 3`
`6 xx x=15-3`
`6 xx x=12`
`x=12:6`
`x=2`
__
`4 xx (x-12)+9=17`
`4 xx (x-12)=17-9`
`4 xx (x-12)= 8`
`x-12=8:4`
`x-12=2`
`x=2+12`
`x=14`
__
`20-2xx(x+4)=4`
`2xx(x+4)=20-4`
`2xx(x+4)=16`
`x+4=16:2`
`x+4=8`
`x=8-4`
`x=4`
\(a,32:\left(3\times X-2\right)=8\\ 3\times X-2=32:8=4\\ 3\times X=4+2=6\\ X=\dfrac{6}{3}=2\\ Vậy:X=2\\ ---\\ b,75:\left(X-18\right)=25\\ X-18=75:25=3\\ X=3+18=21\\ Vậy:X=21\\ ---\\ c,\left(15-6\times X\right)\times243=729\\ 15-6\times X=729:243=3\\ 6\times X=15-3=12\\ X=\dfrac{12}{6}=2\\ Vậy:X=2\\ ---\\ d,4\times\left(X-12\right)+9=17\\ 4\times\left(X-12\right)=17-9=8\\ X-12=8:4=2\\ X=2+12=14\\ Vậy:X=14\\ ---\\ e,20-2\times\left(X+4+4\right)=4\\ 2\times\left(X+4\right)=20-4=16\\ X+4=16:2=8\\ X=8-4=4\\ Vậy:X=4\)
Tìm x:
a)\(\dfrac{1}{3}\sqrt{x-1}+2\sqrt{4x-4}-12\sqrt{\dfrac{x-1}{25}}=\dfrac{29}{15}\)
b)\(\dfrac{3x-2}{\sqrt{x-1}}-\sqrt{x+1}=\sqrt{2x-3}\)
chú ý ai làm hộ mình mình sẽ tích cho!!!!!!
1)P=(1+1/1.3)(1+1/2.4)(1+1/3.5)...(1/49.51)+2/51. Tính P bằng bao nhiêu?
2)Tìm x:a) 15 - |-2+3|.|5+4x|=-19
b) |-|2x+4|-2|=2
3)Tìm số n nguyên sao cho : -124/12-4n=31
4) Tìm số x nguyên sao cho : -3x-15/-2x có giá trị bằng 3