Tìm x: 2^x+3 - 3.2^x+1 = 32.
2x+3-3.2x+1=32
\(2^{x+3}-3.2^{x+1}=32\)
<=> 2^x.2^3-3.2^x.2=32
<=> 2^x.(2^3-3.2)=32
<=> 2^x.2=32
<=>2^x=16
<=>2^x=2^4
=>x=4
Vậy...
2x+3-3.2x+1=32
= 2x . 23 - 3. 21 .2x = 32
2x . 8 - 6 . 2x = 32
2x . (8 - 6 ) = 32
2x . 2 = 32
2x+1 = 32
vì 32 = 25 => x + 1=5
x = 5-1
x = 4
\(2^{x+3}-3.2^{x+1}=32\)
\(2^x.2^3-3.2^x.2=32\)
\(2^x.8-6.2^x=32\)
\(2^x.\left(8-6\right)=32\)
\(2^x.2=32\)
\(2^x=16\)
\(2^x=2^4\)
\(\Rightarrow x=4\)
bài 1 : TÍNH
a ) 2^3 * 2^2 + 7^4 :7^2
b) 6^2 * 47 + 6^2 * 53
c ) 7^2 * 32 + 7^2 * 69 -7
Bài 2 : tìm mũ số n biêt :
a )3* 2^+6=30
b) 30-3*2^n = 24
c)40-5*2^n=20
d)3.2^n + 2^n=16
Bài 3 tìm cơ số tự nhiên , x biết
a) 3 * x ^2 = 75
b) 2 * x^3 = 54
ai giúp mk tik luôn
Bài 3:
a: Ta có: \(3x^2=75\)
\(\Leftrightarrow x^2=25\)
hay \(x\in\left\{5;-5\right\}\)
b: Ta có: \(2x^3=54\)
\(\Leftrightarrow x^3=27\)
hay x=3
Bài 2:
b: Ta có: \(30-3\cdot2^n=24\)
\(\Leftrightarrow3\cdot2^n=6\)
\(\Leftrightarrow2^n=2\)
hay n=1
c: Ta có: \(40-5\cdot2^n=20\)
\(\Leftrightarrow5\cdot2^n=20\)
\(\Leftrightarrow2^n=4\)
hay n=2
d: Ta có: \(3\cdot2^n+2^n=16\)
\(\Leftrightarrow2^n\cdot4=16\)
\(\Leftrightarrow2^n=4\)
hay n=2
bài 1 : TÍNH
a ) 2^3 * 2^2 + 7^4 :7^2
b) 6^2 * 47 + 6^2 * 53
c ) 7^2 * 32 + 7^2 * 69 -7
Bài 2 : tìm mũ số n biêt :
a )3* 2^+6=30
b) 30-3*2^n = 24
c)40-5*2^n=20
d)3.2^n + 2^n=16
Bài 3 tìm cơ số tự nhiên , x biết
a) 3 * x ^2 = 75
b) 2 * x^3 = 54
ai giúp mk tik luôn
a) \(2^3.2^2+7^4:7^2\)
\(=2^5+7^2\)
\(=32+49\)
b) \(6^2.47+6^2.53\)
\(=6^2\left(47+53\right)\)
\(=36.100\)
\(=3600\)
Tìm x biết
10 + 2 . x = 4⁵ : 4³
2 x - 6² : 18 = 3.2²
70 - 5 . ( x- 3 ) = 3.2
\(10+2\cdot x=4^5:4^3\)
\(\Rightarrow10+2\cdot x=4^{5-3}\)
\(\Rightarrow10+2\cdot x=4^2\)
\(\Rightarrow10+2\cdot x=16\)
\(\Rightarrow2\cdot x=16-10\)
\(\Rightarrow2\cdot x=6\)
\(\Rightarrow x=\dfrac{6}{2}=3\)
__________________
\(2\cdot x-6^2:18=3\cdot2^2\)
\(\Rightarrow2\cdot x-36:18=12\)
\(\Rightarrow2\cdot x-2=12\)
\(\Rightarrow2\cdot x=12+2\)
\(\Rightarrow2\cdot x=14\)
\(\Rightarrow x=\dfrac{14}{2}=7\)
_________________
\(70-5\cdot\left(x-3\right)=3\cdot2\)
\(\Rightarrow70-5\cdot\left(x-3\right)=6\)
\(\Rightarrow70-5x+15=6\)
\(\Rightarrow-5x+15=6-70\)
\(\Rightarrow-5x+15=64\)
\(\Rightarrow-5x=64-15\)
\(\Rightarrow-5x=49\)
\(\Rightarrow x=-\dfrac{49}{5}\)
Tìm x
\(\dfrac{1}{4}x-\dfrac{1}{3}=\dfrac{-5}{9}\)
\(2^{x-3}-3.2^x=-92\)
1) \(\dfrac{1}{4}x-\dfrac{1}{3}=\dfrac{-5}{9}\)
\(\Rightarrow\dfrac{1}{4}x=-\dfrac{2}{9}\Rightarrow x=-\dfrac{8}{9}\)
2) \(2^{x-3}-3.2^x=-92\)
\(\Rightarrow2^x\left(2^{-3}-3\right)=-92\)
\(\Rightarrow2^x.\dfrac{-23}{9}=-92\)
\(\Rightarrow2^x=32\Rightarrow x=5\)
Tìm x để
a)5.(x-4)2 -7=13
B)(x+1)+(x+2)+.....+(x+30)
C)2x+3-3.2x+1=32
Nhanh nhé mih đang cẩn gấp
a,5.(x-4) mũ 2-7=13
5.(x-4) mũ 2 =13+7
5.(x-4) mũ 2 =20
(x-4) mũ 2 = 20:5
(x-4)mũ 2= 4
(x-4) mũ 2=2 mũ 2
x-4=2
x=6
Vậy x = 6
b, phần này hình như thiếu gì đó
c,2 mũ x+ 3 - 3.2 mũ x+ 1=32
2 mũ x . 2 mũ 3 - 3 . 2 mũ x . 2 = 32
2 mũ x . 8 -( 3.2).2 mũ x = 32
2 mũ x . 8 -6 . 2 mũ x =32
2 mũ x .( 8- 6) = 32
2 mũ x = 32 : 2
2 mũ x = 16
2 mũ x=2 mũ 4
x = 4
vậy x = 4
k cho mình nha !!!
Tìm x biết :1)-2/3(x-1/4)=1/3(2x-1)
2)1/5.2x+1/3.2x+1=1/5.2x+1+1/3.28
1) \(-\frac{2}{3}\left(x-\frac{1}{4}\right)=\frac{1}{3}\left(2x-1\right)\)
\(-\frac{2}{3}x+\frac{1}{6}=\frac{2}{3}x-\frac{1}{3}\)
\(-\frac{2}{3}x-\frac{2}{3}x=-\frac{1}{3}-\frac{1}{6}\)
\(-\frac{4}{3}x=-\frac{1}{2}\)
\(x=\left(-\frac{1}{2}\right):\left(-\frac{4}{3}\right)\)
\(x=\frac{3}{8}\)
Tìm x thuộc N, biết:
a) 2.3x = 18
b) 2x + 3.2x + 4.2x = 32
c) 3x + 4x = 5x
a, 2.3x = 18
=> 3x = 9 = 32
=> x = 2
b, 2x + 3.2x + 4.2x = 32
=> 2x.(1+3+4) = 32
=> 2x . 8 = 32
=> 2x = 4 = 22
=> x = 2
c, 3x + 4x = 5x
Câu này mik chưa nghĩ ra
a)1.3^x=18
=>3^x=18:2=9
=>3^x=3^2
=>x=2
b)=>2^x.(1+3+4)=32
=>2^x.8=32
=>2^x=4
=>2^x=2^2
=>x=2
2.3x=18
2x+3.2x+4.2x=32
trả lời đúng cho 1 like
2.3x=18
3x=9
3x=32
x=2
2x+3.2x+4.2x=32
2x(3+4+1)=32
2x=4
2x=22
x=2
7.2x+1- 3.2x+1= 32
7.2x+1 - 3.2x+1 = 32
2x+1 ( 7 - 3 ) = 32
2x+1 = 8
x+1 = 3
x=2
\(7\times2^{x+1}-3\times2^{x+1}=32\)
\(\Rightarrow2^{x+1}\left(7-3\right)=32\)
\(\Rightarrow2^{x+1}\times4=32\)
\(\Rightarrow2^{x+1}=32\div4\)
\(\Rightarrow2^{x+1}=8\)
\(\Rightarrow2^{x+1}=2^3\)
\(\Rightarrow x+1=3\)
\(\Rightarrow x=3-1\)
\(\Rightarrow x=2\)
7 : 2x+1 - 3.2x+1 =32
2x+1 ( 7 - 3 ) = 32
2x + 1 = 8
x + 1 = 3
x =2