Tìm x biết 4x=64
Tìm x biết
a, x^23 = 64 . x^20
b, ( 4x-3 )^4 = ( 3-4x )
GIÚP MÌNH VỚI NHÉ MÌNH ĐANG CẦN GẤP
a) x23= 64 . x20
x23: x20= 64
x3= 64
=> x3= 43
=> x =4
Vậy...
a)\(x^{23}=64.x^{20}\)
\(\Leftrightarrow\frac{x^{23}}{x^{20}}=64\)
\(\Leftrightarrow x^3=64\Rightarrow x=4\)
b)\(\left(4x-3\right)^4=3-4x\)
\(\Leftrightarrow\left(3-4x\right)^4=3-4x\)
\(\Leftrightarrow\left(3-4x\right)^3=1\)
\(\Leftrightarrow3-4x=1\)
\(\Leftrightarrow x=\frac{1}{2}\)
tìm x biết:
\(27x^3+\left(x-5\right)^3+64=\left(4x-3\right)^3\)
Tìm x biết
\(\sqrt{64x+64}-\sqrt{25x+25}+\sqrt{4x+4}=20\)
<=> \(\sqrt{64\left(x+1\right)}-\sqrt{25\left(x+1\right)}+\sqrt{4\left(x+1\right)}=20\)
<=> \(8\sqrt{\left(x+1\right)}-5\sqrt{\left(x+1\right)}+2\sqrt{\left(x+1\right)}=20\)
<=> . \(5\sqrt{\left(x+1\right)}=20\)
<=> \(\sqrt{\left(x+1\right)}=4\)
=> x+1=16
=> x=15
Tìm số tự nhiên x biết:
a) x - 32 : 16 = 48 b) 88 - 3 . 7 + x = 64
c) 5 + 4 x : 3 - 121 : 11 = 4 d) 15 - 2 3 x + 1 = 11 . 13 - 130
Tìm x
a, x\(^2\)-64=0
b, 4x\(^2\)-4x+1=0
c, 9-6x+x\(^2\)=0
a) \(x^2-64=0\)
\(\Leftrightarrow\left(x-8\right)\left(x+8\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=8\\x=-8\end{matrix}\right.\)
b) \(4x^2-4x+1=0\)
\(\Leftrightarrow\left(2x-1\right)^2=0\Leftrightarrow2x-1=0\)
\(\Leftrightarrow x=\dfrac{1}{2}\)
c) \(9-6x+x^2=0\)
\(\Leftrightarrow\left(x-3\right)^2=0\)
\(\Leftrightarrow x-3=0\Leftrightarrow x=3\)
a: Ta có: \(x^2-64=0\)
\(\Leftrightarrow\left(x-8\right)\left(x+8\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=8\\x=-8\end{matrix}\right.\)
b: Ta có: \(4x^2-4x+1=0\)
\(\Leftrightarrow\left(2x-1\right)^2=0\)
hay \(x=\dfrac{1}{2}\)
c: ta có: \(x^2-6x+9=0\)
\(\Leftrightarrow\left(x-3\right)^2=0\)
hay x=3
Tìm số tự nhiên x biết:
a) x – 32 : 16 = 48
b) 88 – 3.(7+x) = 64
c) (5+4x) : 3 – 121 : 11 = 4
d) 15 – 2(3x+1) = 11.13 – 130
a) x – 32 : 16 = 48 ó x – 2 = 48 ó x = 48 + 2 ó x = 50
b) 88 – 3.(7+x) = 64 ó 3.(7+x) = 88 – 64 ó 7 + x = 24:3 ó x = 8 – 7 ó x = 1
c) (5+4x) : 3 – 121 : 11 = 4 ó (5+4x) : 3 – 11 = 4 ó (5+4x) : 3 = 4 + 11 ó 5+4x = 15.3 ó 4x = 45 – 5 ó 4x = 40 ó x = 10
d) 15 – 2(3x+1) = 11.13 – 130 ó 15 – 2(3x+1) = 143 – 130 ó 15 – 2(3x+1) = 13
ó 2(3x+1) = 15 – 13 ó 3x + 1 = 2:2 ó 3x = 1 – 1 ó 3x = 0 ó x = 0
tìm x biết
a. x^3-64=0
b. (2x-3)^2-(x+5)^2=0
c.(x^3-x^2)-4x^2+8x-4=0
a/ => x3 = 64 => x3 = 43 => x = 4
b/ => 4x2 - 12x + 9 - x2 - 10x - 25 = 0
=> 3x2 - 22x - 16 = 0
=> (x - 8)(3x + 2) = 0
=> x - 8 = 0 => x = 8
hoặc 3x + 2 = 0 => 3x = -2 => x = -2/3
Vậy x = 8 ; x = -2/3
c/ => x3 - x2 - 4x2 + 8x - 4 = 0
=> x3 - 5x2 + 8x - 4 = 0
=> (x - 2)2 (x - 1) = 0
=> (x - 2)2 = 0 => x - 2 = 0 => x = 2
hoặc x - 1 = 0 => x = 1
Vậy x = 2 ; x = 1
Tính nhẩm biểu thức : 2565 . 65 - 565 . 64
áp dụng kết quả trên tìm số tự nhiên x biết : 104x+1 +30565 = 2565.65 - 565.64
đầu tiên ta tính nhẩm
2565.65-565,64
=2565.(64+1)-565.64
=(2565.64+2565)-565.64
=2565.64+2565-565.64
=64.(2565-565)+2565
=64.2000+2565
=128000+2565
=130565
áp dụng
10^4x+1+30565=2565.65-565.64
10^4x+1+30565=130565
10^4x+1=130565-30565=100000
10^4x+1=10^5
suy ra 4x+1=5
4x=5-1=4
4x=4 vậy x=1
tick cho mik nha mỏi tay quá đi mất
Tìm x biết
a,x3+64=0
b,(2x-1)2-(x+3)2=0
c,4x2(x-2)=x-2
a) \(x^3+64=0\)
\(x^3=0-64\)
\(x^3=-64\)
\(x^3=-4^3\)
\(\Rightarrow x=-4\)
b)Tương tự
tìm x biết
(x+1)2=81
(x+5)3=-64
(2x-3)2=9
(4x+1)3=27
\(\left(x+1\right)^2=81\)
\(\Rightarrow\left(x+1\right)^2=9^2\)
\(\Rightarrow x+1=9\)
\(\Rightarrow x=9-1=8\)
Vậy x = 8
b, \(\left(x+5\right)^3=-64\)
\(\Rightarrow\left(x+5\right)^3=\left(-4\right)^3\)
\(\Rightarrow x+5=-4\)
\(\Rightarrow x=\left(-4\right)-5\)
\(\Rightarrow x=-9\)
Vậy x = -9
c, \(\left(2x-3\right)^2=9\)
\(\Rightarrow\left(2x-3\right)^2=3^2\)
\(\Rightarrow2x-3=3\)
\(\Rightarrow2x=6\)
\(\Rightarrow x=3\)
Vậy x = 3
d, \(\left(4x+1\right)^3=27\)
\(\Rightarrow\left(4x+1\right)^3=3^3\)
\(\Rightarrow4x+1=3\)
\(\Rightarrow4x=2\)
\(\Rightarrow x=\frac{1}{2}\)
Vậy x = \(\frac{1}{2}\)