Tìm x
52x-3 - 2 . 52 = 52 . 3
Tìm x biết:
1. 52x - 3 - 2 . 52 = 52 . 3
2. 41 - 2x+1 = 9
3. 65 - 4x+2 = 20140
1: =>\(5^{2x-3}=5^2\cdot3+5^2\cdot2=5^2\cdot5=5^3\)
=>2x-3=3
=>2x=6
=>x=3
2: \(41-2^{x+1}=9\)
=>\(2^{x+1}=32\)
=>x+1=5
=>x=4
3: =>\(4^{x+2}=65-1=64\)
=>x+2=3
=>x=1
\(5^{2x-3}-2.5^2=5^2.3\\ 5^{2x-3}=5^2.3+5^2.2\\ 5^{2x-3}=5^2.\left(3+2\right)\\ 5^{2x-3}=5^2.5\\ 5^{2x-3}=5^3\\ \Rightarrow2x-3=3\\ 2x=3+3\\ 2x=6\\ x=\dfrac{6}{2}\\ Vậy:x=3\)
\(41-2^{x+1}=9\\ 2^{x+1}=41-9\\ 2^{x+1}=32=2^5\\ \Rightarrow x+1=5\\ \Leftrightarrow x=5-1=4\\ ---\\ 65-4^{x+2}=2014^0\\ 65-4^{x+2}=1\\ 4^{x+2}=65-1\\ 4^{x+2}=64=4^3\\ \Rightarrow x+2=3\\ Vậy:x=1\)
52×x-3-2×52 = 52×3
Bài 1: tìm x
c) \(|\) x \(|\) = 3,5
d) \(|\) x \(|\) = -2,7
e) \(|\) 1 - x \(|\) + 0,73 = 3
f) 52 . 73 . 11x + 52 . 72 .11 = 0
g) (3 . 5 + 5 . 7)x + ( 3 . 5 + 5 . 7) + (3 . 5 + 5 . 7) = 0
h) 52 . 72 . 112x - 52 . 72 . 114 = 0
l) \(|\) x + \(\dfrac{3}{4}\) \(|\) - 5 = -2
c) \(\left|x\right|=3,5\Rightarrow\left[{}\begin{matrix}x=3,5\\x=-3,5\end{matrix}\right.\)
d) \(\left|x\right|=-2,7\Rightarrow x\in\varnothing\)
l) \(\left|x+\dfrac{3}{4}\right|-5=-2\Rightarrow\left|x+\dfrac{3}{4}\right|=3\)
\(\Rightarrow\left[{}\begin{matrix}x+\dfrac{3}{4}=3\\x+\dfrac{3}{4}=-3\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=3-\dfrac{3}{4}\\x=-3-\dfrac{3}{4}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{9}{4}\\x=\dfrac{15}{4}\end{matrix}\right.\)
Đính chính câu l \(x=-\dfrac{15}{4}\) không phải \(x=\dfrac{15}{4}\)
c) x = 3,5 hoặc -3,5
d) x = -2,7
e) x = -1,27
f) x = 0
g) x = -2
h) x = 0
l) x = 9/4
x = -15/4
52x – 3 – 2 . 52 = 52. 3
5²ˣ⁻³ - 2.5² = 5².3
5²ˣ⁻³ - 2.25 = 25.3
5²ˣ⁻³ - 50 = 75
5²ˣ⁻³ = 75 + 50
5²ˣ⁻³ = 125
5²ˣ⁻³ = 5³
2x - 3 = 3
2x = 3 + 3
2x = 6
x = 6 : 2
x = 3
52x-3 - 2×52 = 52×3
52x-3 - 2 x 52 = 52 x3
52x-3 - 2x52 = 156
52x-3 - 104 = 156
52x-3 =156 + 104
52x-3 = 260
x-3 = 260:52
x-3 = 5
x=5+3
x=8
Vậy x=8
Bài 2: Thực hiện phép tính (tính nhanh nếu có thể )
a) 78 : 76 + 52 . 1080
=
=
b) 212 : 29 + 970.3
=
=
a) 92 : 90 - 2 .24
=
=
=
Bài 3: Tìm số tự nhiên x, biết:
a) 31 + x2 = 40
b) 52 – x2 = 27
c) x2 – 13 = 3
52x-3-2 . 52=52.3 tìm số tự nhiên x biết
\(\Leftrightarrow5^{2x-3}-2.25=25.3\\ \Leftrightarrow5^{2x-3}-50=75\\ \Leftrightarrow5^{2x-3}=125\\ \Leftrightarrow2x-3=3\\ \Leftrightarrow x=3\)
Tìm số tự nhiên x,biết:
a)58 + 7x = 100
b) ( x –12):12=12
c) x -56 : 4= 16
d) 101 +(36 –4x) =105
e) 2(x-51) = 2.23+ 20
f) 10 -(x –3): 2 = 72–110
g) 2x –49 = 5.32h) [(8x -12) : 4].33= 36
i) 52x –3–2 . 52= 52. 3 k) (x3–7) : 4 = 5
a: 7x+58=100
nên 7x=42
hay x=6
c: x-56:x=16
nên x-14=16
hay x=30
c)x - 56 : 4 = 16
x - 56 = 16 : 4
x- 56 = 4
x =4 + 56
x = 60
d)101 + (36 - 4x) = 105
(36- 4x ) = 105 - 101
36 - 4x = 4
4x = 36 - 4
4x = 32
x = 32:4
x = 8
a) 58 + 7x = 100
7x = 100 - 58
7x = 42
x = 42 : 7
x = 6
b) (x - 12) : 12 = 12
x - 12 = 12 . 12
x - 12 = 144
x = 144 + 12
x = 156
tim x 52x-3-2×52 = 52×3