Tìm x biết :
a) 19992x - 6 = 1
b) 2x x 4 = 128
c) ( 2x + 1 ) 3 = 125
Câu 4 : Tìm x, biết.
a) 2^x.4 = 128 b) (2x + 1)^3 = 125 c) 2x – 2^6 = 6 d) 49.7^x = 2401\(a,2^x.4=128\\2^x.2^2=2^7\\ 2^x=\dfrac{2^7}{2^2}=2^{7-2}=2^5\\ Vậy:x=5\\ ----\\ b,\left(2x+1\right)^3=125=5^3\\ \Rightarrow 2x+1=5\\ 2x=5-1=4\\ x=\dfrac{4}{2}=2\\ ----\\ c,2x-2^6=6\\ 2x=6+2^6=6+64\\ 2x=70\\ x=\dfrac{70}{2}=35\\ ----\\ d,49.7^x=2401\\ 7^x=\dfrac{2401}{49}=49=7^2\\ Vậy:x=2\)
Câu 3: Tìm x ∈ N, biết:
a) 3 x . 3 = 243 b) 2 x . 162 = 1024 c) 64.4x = 168 d) 2 x = 16Câu 4 : Tìm x, biết. a) 2 x .4 = 128 b) (2x + 1)3 = 125 c) 2x – 2 6 = 6 d) 49.7x = 24013:
a: 3^x*3=243
=>3^x=81
=>x=4
b; 2^x*16^2=1024
=>2^x=4
=>x=2
c: 64*4^x=16^8
=>4^x=4^16/4^3=4^13
=>x=13
d: 2^x=16
=>2^x=2^4
=>x=4
Tìm số tự nhiên x biết
a) 2x-13=1(có giải thích)
b) 5^5 :(7+x)=5^3
c) 4^2+4^x=6^6:6^4
d) (2x-1)^3=125
Tìm x biết,
a) 7/12 - 1/4 : (-4/11-x)=125%
b)1/2x -1/3 = 2/3 x -5/6
c) |x-1/2|
a. 7/12 - 1/4 : ( -4/11 - x ) = 125%
=> 1/4 : ( -4/11 - x ) = 7/12 - 5/4 = -2/3
=> -4/11 - x = 1/4 : -2/3
=> -4/11 - x = -3/8
=> x = -4/11 - ( -3/8 )
=> x = 1/88
b. 1/2x - 1/3 = 2/3x - 5/6
=> 1/2x - 2/3x = 1/3 - 5/6
=> -1/6x = -1/2
=> x = -1/2 : -1/6
=> x = 3
3) Tìm x của N biết a) 80 - ( 2 + 2x ) : 2 = 40 b) 11^2 - 121 = 0 c) 5^x+3 - 7 × 5^2 = 5^2 × 18 d) x^10 = x e) x^10 = 1^x g) ( 2x - 15 )^5 = ( 2x - 15 )^3 4) Thực hiện phép tính a) 5^3 ÷ 5^2 + 2^2 × 3 b) 4^3 × 125 - 125 ÷ 5^2 c) 6^2 × 28 + 72 × 6^2 d) 5^6 ÷ 5^4 + 3 × 3^2 - 80 e) 2^3 × 19 - 2^3 × 14 × 1^2021
tìm x biết
a,2^11=x
b, 2^2016=x
c,(2x+1)^3=125
d, (2x-3)^2=625
e(2x-4)^2014+(3x-6)^2016< hoặc bằng 0
tìm x biết
a) /2x-50\+/5x-125\-/3x+75/=100
b) 2x+/x-3\=6
c) 3x-1= /2x-1/
MK chỉ làm câu b và c thôi nha
b)2x+|x-3|=6
TH1:2x+x-3=6
3x-3=6
3x=9
x=3
TH2:2x+-(x-3)=6
2x-x+3=6
x+3=6
x=3
Vậy x=3
c)3x-1=|2x-1|
TH1:3x-1=2x-1
3x-1-2x+1=0
x=0
TH2:3x-1=-(2x-1)
3x-1=1+2x
3x-1-1-2x=0
x-2=0
x=2
Vậy x=0;2
tìm x biết: a) (2x-1)4=16 b) (2x+1)=125
a) \(\left(2x-1\right)^4=16\)
\(\)TH1: \(\left(2x-1\right)^4=2^4\)
\(=>2x-1=2\)
\(2x=2+1\)
\(2x=3\)
\(x=\dfrac{3}{2}\)
TH2: \(\left(2x-1\right)^4=\left(-2\right)^4\)
\(=>2x-1=-2\)
\(2x=-2+1\)
\(2x=-1\)
\(x=\dfrac{-1}{2}\)
Vậy x = \(\dfrac{3}{2}\) hoặc x = \(\dfrac{-1}{2}\)
________--
b) \(\left(2x+1\right)^3=125\) ( mình nghĩ đề bài đúng là vầy )
\(\left(2x+1\right)^3=5^3\)
\(=>2x+1=5\)
\(2x=5-1\)
\(2x=4\)
\(x=4:2\)
\(x=2\)
Vậy x = \(2\)
bài 1 : tìm x biết ;
a) 2x + 3 = 5 b)(2x - 3)2= 9 c)3x + 4 = 2x - 7 d)(4x - 1)3= 27 e) (x - 7) . 2 =3(2x +4) f) 52x-1= 125 g) 3.(x + 6) - 2x = 3 + 12x
Nếu bài dễ thì cố gắng tự làm bạn nhé.
Bài 1:
a) \(2x+3=5\)
\(\Leftrightarrow2x=5-3=2\)
\(\Leftrightarrow x=2:2=1\)
Vậy: x=1
b) \(\left(2x-3\right)^2=9\)\(=3^2=\left(-3\right)^2\)
\(\Rightarrow\left[{}\begin{matrix}2x-3=3\\2x-3=-3\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\left(3+3\right):2=3\\x=\left(-3+3\right):2=0\end{matrix}\right.\)
Vậy: \(x\in\left\{3;0\right\}\)
c) \(3x+4=2x-7\)
\(\Leftrightarrow2x-3x=7+4\)
\(\Leftrightarrow-1x=11\)
\(\Leftrightarrow x=-11\)
Vậy: x=-11
d) \(\left(4x-1\right)^3=27\)\(=3^3\)
\(\Rightarrow4x-1=3\)
\(\Leftrightarrow4x=3+1=4\)
\(\Leftrightarrow x=4:4=1\)
Vậy: x=1
e) \(\left(x-7\right).2=3.\left(2x+4\right)\)
\(\Leftrightarrow2x-14=6x+12\)
\(\Leftrightarrow2x-6x=12+14\)
\(\Leftrightarrow-4x=26\)
\(\Leftrightarrow x=\frac{26}{-4}=\frac{13}{-2}\)
Vậy: \(x=\frac{13}{-2}\)