Tìm x:
1) \(\left(2x-15\right)^5=\left(2x-15\right)^3\)
2) \(2\cdot3^x=10\cdot3^{12}+8\cdot27^4\)
3) \(\left(19x+2\cdot5^2\right):14=\left(13-8\right)^2-4^2\)
Tìm x:
1) \(2\cdot3^x=10\cdot3^{12}+8\cdot27^4\)
2) \(\left(19x+2\cdot5^2\right):14=\left(13-8\right)^2-4^2\)
\(2.3^x=10.3^{12}+8.27^4\)
\(2.3^x=10.531441+8.531441\)
\(2.3^x=\left(10+8\right).531441\)
\(2.3^x=18.531441\)
\(2.3^x=9565938\)
\(3^x=9565938:2\)
\(3^x=4782969\)
\(3^x=3^{14}\)
\(\Rightarrow x=14\)
1. Tìm x
a) \(2^x+5=21\)
b) \(2^x-1+3^2=5^2+2\cdot5\)
c) \(\left(2x-1\right)^3+5=130\)
d) \(5^{2x-3}-2\cdot5^2=5^2\)
e) \(3^{2x+1}-2=3^2+\left[5^2-3\left(2^2-1\right)\right]\)
f) \(\left(7^x-11\right)^3=2^5\cdot5^2+200\)
g) \(2\cdot3^x=10\cdot3^{12}+8\cdot27^4\)
a) \(2^x+5=21\)
\(\Rightarrow2^x=21-5=16\Rightarrow2^x=2^4\)
Vậy x = 4
b) \(2^x-1+3^2=5^2+2.5\)
\(\Rightarrow2^x-1+9=35\)
\(\Rightarrow2^x=35-9+1=27\)
Vậy x không có giá trị
c;d;e;f làm tương tự
1: \(15-\left\{2\cdot\left[x-\left(2x-4\right)\cdot5\right]\cdot3\cdot\left(x+1\right)\right\}=12-x\)
\(15-\left\{2.\left[\left(2x-4\right).5\right].3.\left(x+1\right)\right\}=12-x\)
\(15-\left\{\left[10x-20\right].6.\left(x+1\right)\right\}=12-x\)
\(15-\left\{10x-20.6x+1\right\}=12-x\)
\(15-\left\{10x-120x+1\right\}=12-x\)
\(15-\left(-110x\right)-1=12-x\)
\(15+110x-1=12-x\)
\(110x+x=12-15+1\)
\(111x=-2\)
\(x=\dfrac{-2}{111}\)
1:rút gọn
\(\dfrac{11\cdot3^{22}\cdot3^7-9^{15}}{\left(2\cdot3^{14}\right)^2}\)
2: tìm x
\(\dfrac{3\cdot\left(x-2\right)}{4}-\dfrac{2\cdot\left(1+2x\right)}{3}=1\dfrac{1}{4}-5\cdot\dfrac{\left(1+3x\right)}{6}-\dfrac{x-2}{12}\)
\(\dfrac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right)^2}\)
\(=\dfrac{11.3^{29}-\left(3^2\right)^{15}}{2^2.3^{28}}\)
\(=\dfrac{11.3^{29}-3^{30}}{2^2.3^{28}}\)
\(=\dfrac{3^{29}\left(11-3\right)}{2^2.3^{28}}\)
\(=\dfrac{3^{29}.2^3}{2^2.3^{28}}\)
\(=\dfrac{3.2}{1.1}=6\)
1.tính c = \(\left(1\cdot2\cdot3\cdot4+2\cdot3\cdot4\cdot5+...+18\cdot19\cdot20\cdot21\right)-5-10-15-...-200\)
2. tính d = \(\dfrac{1}{1\cdot2\cdot3}+\dfrac{1}{2\cdot3\cdot4}+...+\dfrac{1}{18\cdot19\cdot20}-\dfrac{3}{1\cdot2}-\dfrac{3}{2\cdot3}-...-\dfrac{3}{19\cdot20}\)
3.tìm x: \(2\left(x-3\right)-3\left(1-2x\right)=4+4\left(1-x\right)\)
4.tìm x: \(\dfrac{x-2}{2}-\dfrac{1+x}{3}=\dfrac{4-3x}{4}-1\)
giải nhanh giùm tớ nhé. ghi cả lời giả ra kìa
3/ \(2\left(x-3\right)-3\left(1-2x\right)=4+4\left(1-x\right)\)
\(\Leftrightarrow2x-6-3+6x=4+4-4x\)
\(\Leftrightarrow8x-9=8-4x\)
\(\Leftrightarrow8x+4x=8+9\)
\(\Leftrightarrow12x=17\)
\(\Leftrightarrow x=\dfrac{17}{12}\)
Vậy \(x=\dfrac{17}{12}\)
4/ \(\dfrac{x-2}{2}-\dfrac{1+x}{3}=\dfrac{4-3x}{4}-1\)
\(\Leftrightarrow6\left(x-2\right)-4\left(1+x\right)=3\left(4-3x\right)-12\)
\(\Leftrightarrow6x-12-4-4x=12-9x-12\)
\(\Leftrightarrow6x-4-4x=12-9x\)
\(\Leftrightarrow2x-4=12-9x\)
\(\Leftrightarrow2x+9x=12+4\)
\(\Leftrightarrow11x=16\)
\(\Leftrightarrow x=\dfrac{16}{11}\)
Vậy \(x=\dfrac{16}{11}\)
1. Tìm x
a) \(2^x+5=21\)
b) \(2^x-1+3^2=5^2+2\cdot5\)
c) \(\left(2x-1\right)^3+5=130\)
d) \(5^{2x-3}-2\cdot5^2=5^2\)
e) \(3^{2x+1}-2=3^2+\left[5^2-3\left(2^2-1\right)\right]\)
f) \(\left(7x-11\right)^3=2^5\cdot5^2+200\)
g) \(2\cdot3^x=10\cdot3^{12}+8\cdot27^4\)
Giúp với nha
a) \(2^x+5=21\)
\(2^x=21-5\)
\(2^x=16\)
\(2^x=2^4\)
\(\Rightarrow x=4\)
Vậy \(x=4\)
a ) \(2^x+5=21\)
\(2^x=21-5\)
\(2^x=16\)
\(2^x=2^4\)
\(\Rightarrow x=4\)
Rút gọn:
a,\(A=\frac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6}\)
b,\(B=\left(1+\frac{1}{1\cdot3}\right)\left(1+\frac{1}{2\cdot4}\right)\left(1+\frac{1}{3\cdot5}\right)...\left(1+\frac{1}{2014\cdot2016}\right)\)
\(\dfrac{99}{100}:\left(\dfrac{1}{4}-\dfrac{1}{12}+\dfrac{1}{3}\right)-\left(\dfrac{-7}{5}\right)^2\)
\(\dfrac{13}{15}\cdot0,25\cdot3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\)
a: \(=\dfrac{99}{100}:\left(\dfrac{3}{12}-\dfrac{1}{12}+\dfrac{4}{12}\right)-\dfrac{49}{25}\)
\(=\dfrac{99}{100}:\dfrac{1}{2}-\dfrac{49}{25}\)
\(=\dfrac{99}{50}-\dfrac{98}{50}=\dfrac{1}{50}\)
b: \(=\dfrac{13}{15}\cdot\dfrac{1}{4}\cdot3+\left(\dfrac{32}{60}-1-\dfrac{19}{60}\right):\dfrac{47}{24}\)
\(=\dfrac{39}{60}+\dfrac{-19}{60}\cdot\dfrac{24}{47}\)
=459/940
Bài 2 : Tìm x , biết :
a, \(\left(19x+2\cdot5^2\right)\text{ : }14=\left(13-8\right)^2-4^2\)
b, \(x+\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+30\right)=1240\)
c, \(11-\left(-53+x\right)=97\)
d, \(-\left(x+84\right)+213=-16\)
e, \(13-12+11+10-9+8-7-6+5-4+3+2-1=x\)
\(a,\left(19x+2.5^2\right):14=\left(13-8\right)^2-4^2\)
\(\Leftrightarrow\left(19x+50\right):14=5^2-4^2\)
\(\Leftrightarrow\left(19x+50\right):14=9\)
\(\Leftrightarrow19x+50=126\)
\(\Leftrightarrow19x=76\Leftrightarrow x=4\)
b) x + ( x + 1 ) + ( x + 2 ) + ... + ( x + 30 ) = 1240
x + x + 1 + x + 2 + ... + x + 30 = 1240
( x + x + ... + x ) + ( 1 + 2 + ... + 30 ) = 1240
Số số hạng là : ( 30 - 1 ) : 1 + 1 = 30 ( số )
Tổng là : ( 30 + 1 ) . 30 : 2 = 465
=> 31x + 465 = 1240
=> 31x = 775
=> x = 25
Vậy........
c) 11 - ( -53 + x ) = 97
11 + 53 - x = 97
64 - x = 97
x = 64 - 97
x = -33