Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Bài 62 : Tìm x e N biết :
a) 16x < 1284
b) 5x . 5x+1 .5x+ \(\le\)100...............0 : 28
18 chữ số 0
a: \(\dfrac{4^5+4^5+4^5+4^5}{3^5+3^5+3^5+3^5}\cdot\dfrac{6^5+6^5+6^5+6^5+6^5+6^5}{2^5+2^5+2^5+2^5+2^5+2^5}=2^x\)
\(\Leftrightarrow2^x=\dfrac{4^5}{3^5}\cdot\dfrac{6^5}{2^5}=4^5=2^{10}\)
=>x=10
b: \(\left(x-1\right)^{x+4}=\left(x-1\right)^{x+2}\)
\(\Leftrightarrow\left(x-1\right)^{x+2}\left[\left(x-1\right)^2-1\right]=0\)
\(\Leftrightarrow x\left(x-1\right)^{x+2}\cdot\left(x-2\right)=0\)
hay \(x\in\left\{0;1;2\right\}\)
c: \(6\left(6-x\right)^{2003}=\left(6-x\right)^{2003}\)
\(\Leftrightarrow5\cdot\left(6-x\right)^{2003}=0\)
\(\Leftrightarrow6-x=0\)
hay x=6
a)16x<1284
=>(24)x<(27)4
=>24x<228
<=>4x<28
<=>x<7
=>x={0;1;2;3;4;5;6}
b)5x.5x+1.5x+2<100...0:218
<=>53x+3<1018:218=(10:2)18=518
<=>3x+3<18
<=>3x<15
<=>x<5
<=>x={0;1;2;3;4}
a) 16x < 1284
(24)x<(27)4
24x<228
=>4x<28
=>x<28:4
=>x<7
mà x\(\in\)N nên
0\(\le\)x<7
b) 5x . 5x + 1 . 5x + 2 < 10.....0 : 218
5x+x+1+x+2<1018:218
53x+3<(10:2)18
53x+3<518
=>3x+3<18
=>3x<18-3
=>3x<15
=>x<15:3
=>x<5 mà x\(\in\)N nên
0\(\le\)x<5
Bài 1 :
a, Ta có : \(\left(-123\right)+\left|-13\right|+\left(-7\right)\)
= \(\left(-123\right)+13+\left(-7\right)=\left(-117\right)\)
b, Ta có : \(\left|-10\right|+\left|45\right|+\left(-\left|-455\right|\right)+\left|-750\right|\)
= \(10+45-455+750=350\)
c, Ta có : \(-\left|-33\right|+\left(-15\right)+20-\left|45-40\right|-57\)
= \(\left(-33\right)+\left(-15\right)+20-5-57=-90\)
a)5^36=(5^3)^12=125^12
11^24=(11^2)^12=121^12
Vi 125^12>121^12=>5^36>11^24
1+3+5+...+x=1600
=(x+1).[(x-1):2+1] /2 =1600
=(x+1).(x+1) /2 =1600
=(x+1)^2:2=40^2
=(x+1):2=40
=x+1=80
=x=79