7.3^x - 5^x+2 = 3^x+4 - 5^x+3
\(5.3^x=5.3^4\)
\(5.3^x=7.3^5-2:3^5\)
5.3x = 5.34
=> x = 4
5.34 = 7.35 - 2.35
= 35 . (7 - 2)
= 5. 35
=> 3x = 35
=> x = 5
a) Ta có: \(5\cdot3^x=5\cdot3^4\)
\(\Leftrightarrow3^x=3^4\)
hay x=4
Bài 6: 1) 3^x+2+4.3^x+1=7.3^6 2)5^x+4-3.5^x+3=2.5^11 3)4^x+3-3.4^x+1=13.4^11
Lời giải:
1.
$3^{x+2}+4.3^{x+1}=7.3^6$
$3^{x+1}.3+4.3^{x+1}=7.3^6$
$3^{x+1}(3+4)=7.3^6$
$3^{x+1}.7=7.3^6$
$\Rightarrow 3^{x+1}=3^6$
$\Rightarrow x+1=6$
$\Rightarrow x=5$
2.
$5^{x+4}-3.5^{x+3}=2.5^{11}$
$5^{x+3}.5-3.5^{x+3}=2.5^{11}$
$5^{x+3}(5-3)=2.5^{11}$
$2.5^{x+3}=2.5^{11}$
$\Rightarrow 5^{x+3}=5^{11}$
$\Rightarrow x+3=11$
$\Rightarrow x=8$
3.
$4^{x+3}-3.4^{x+1}=13.4^{11}$
$4^{x+1}.4^2-3.4^{x+1}=13.4^{11}$
$4^{x+1}.16-3.4^{x+1}=13.4^{11}$
$13.4^{x+1}=13.4^{11}$
$\Rightarrow 4^{x+1}=4^{11}$
$\Rightarrow x+1=11$
$\Rightarrow x=10$
Tìm x,biết
A) (-3)^2x=9^5
B) 9.5^ x-3=6.5^6+3.5^6
C) 5^x+4-3.5^x+3=5^11.2
D) 3^x+2+4.3^x+1=7.3^6
E) 5^x+3=10^5.6^3:4^4.3^3
Tìm số nguyên x , nếu biết
1. 7.4^x=7.4^3
2.3/2.5^x =3/2.5^12
3 . 2^x=2.2^8
4. 5.3^x=7.3^5-2.3^5
1) \(7.4^x=7.4^3\Leftrightarrow4^x=4^3;x=3\)
2) \(\frac{3}{2.5^x}=\frac{3}{2.5^{12}}\Leftrightarrow5^x=5^{12};x=12\)
\(2^x=2.2^8=2^9;x=9\)
4) \(5.3^x=7.3^5-2.3^5\Leftrightarrow5.3^x=3^5.\left(7-2\right)\)
\(\Leftrightarrow3^5.x=3^5.5;x=5\)
a,-12(x-5)+7(3-x)=5
b,-12x-(-12).5+7.3-7.x=5
c,30(x+2)-6(x-3)-24.x=100
a) \(-12\left(x-5\right)+7\left(3-x\right)=5\)
\(-12x+60+21-7x=5\)
\(-19x=5-60-21\)
\(-19x=-76\)
\(x=4\)
vậy \(x=4\)
tương tự
(x+5)-2(x-7)+5.(8+x)-7.3(3-2x)=(42-x)-5.(7x-7)+(4x-1)+3462
a, \(5.3^x=5.3^4\)
b, \(5.3^x=7.3^5-2:3^5\)
c, \(5^{x+4}-3.5^{x+3}=2.5^{11}\)
d, \(2^x+2^{x+1}+2^{x+2}+2^{x+3}+2^{x+4}+2^{x+5}=480\)
Làm đầy theo tính ra kết quả thì mk với tik
c, \(5^{x+4}-3\cdot5^{x+3}=2\cdot5^{11}\)
\(\Leftrightarrow5^{x+3}\cdot5-3\cdot5^{x+3}=2\cdot5^{11}\)
\(\Leftrightarrow5^{x+3}\left(5-3\right)=2\cdot5^{11}\)
\(\Leftrightarrow5^{x+3}\cdot2=2\cdot5^{11}\)
\(\Leftrightarrow5^{x+3}=5^{11}\)
\(\Leftrightarrow x+3=11\)
\(\Leftrightarrow x=8\)
Vậy x = 8
d, \(2^x+2^{x+1}+2^{x+2}+2^{x+3}+2^{x+4}+2^{x+5}=480\)
\(\Leftrightarrow2^x\left(1+2+2^2+2^3+2^4+2^5\right)=480\)
\(\Leftrightarrow2^x\cdot63=480\)
\(\Leftrightarrow2^x=\frac{160}{21}\)
\(\Leftrightarrow x\approx2,93\)
bn nào trả lời hộ mk ik
đang gấp !!!
Tìm x biết
1)\(3^{x+2}+4\cdot3^{x+1}=7.3^6\)
2)\(5.3^{x+6}=2.3^5+3.3^5\)
1) Tìm số nguyên x, biết :
a) 3x + 2 + 4 . 3x + 1 = 7.36
b) 4x + 3 - 3.4x + 1 = 13 . 411
c) 3.5 x + 2 + 4 . 5 x - 3 = 19 . 510
1) Tìm số nguyên x, biết :
a) 3x + 2 + 4 . 3x + 1 = 7.36
3x + 1 ( 3 + 4) = 7.36
3x + 1 .7 = 7.36
=> x + 1 = 6
=> x = 5
b) 4x + 3 - 3.4x + 1 = 13 . 411
4x + 1 ( 42 - 3) = 13 . 411
4x + 1 . 13 = 13 . 411
=> x + 1 = 11
=> x = 10