47 – 7(x + 5) = 2^5.3
Rút gọn các phân số sau:
a) − 7 .3 + 4. − 6 − 5 .3 + 2.3
b) 3.6 + 2.9.5 − 18. − 4 7. − 7 + 12. − 7 + 7
a) − 7 .3 + 4. − 6 − 5 .3 + 2.3 = − 45 = 9 = 6
b) 3.6 + 2.9.5 − 18. − 4 7. − 7 + 12. − 7 + 7 = 18. 1 + 5 + 4 − 7 . 7 + 12 − 1 = 18.10 − 7.18 = − 10 7
\(5.3^x=5.3^4\)
\(5.3^x=7.3^5-2:3^5\)
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
A. 100-7{x-5}=58 B. 5.3 mũ 2 -- 32 : 4 mũ 2
\(a,\Rightarrow7\left(x-5\right)=100-58=42\\ \Rightarrow x-5=6\\ \Rightarrow x=11\\ b,=5\cdot9-2^5:2^4=45-2=43\)
1) 5.2²+ (x+3)=5² 6) 4³ - (x-2)=5²
2) 2³+(x-3²)= 5³-4³ 7) 3⁴+ (x+5)=5.3²
3) 3.2 + (x+5²)=10² 8) 2³.5 - (x+ 3²)=10
4) 2⁶+(5+x)= 3⁴ 9) 3³ - (x+2⁴)=7
5) 5+(x + 3³)= 2⁶ 10) 7² - (15+x)=5.2²
1; 5.22 + (\(x\) + 3) = 52
5.4 + (\(x\) + 3) = 25
20 + (\(x\) + 3) = 25
\(x\) + 3 = 25 - 20
\(x+3\) = 5
\(x\) = 5 - 3
\(x\) = 2
Vậy \(x=2\)
2; 23 + (\(x\) - 32) = 53 - 43
8 + (\(x\) - 9) = 125 - 64
8 + (\(x\) - 9) = 61
\(x\) - 9 = 61 - 8
\(x\) - 9 = 53
\(x\) = 53 + 9
\(x\) = 62
Vậy \(x\) = 62
3; 3.2 + (\(x\) + 52) = 102
6 + (\(x\) + 25) = 100
\(x\) + 25 = 100 - 6
\(x\) + 25 = 94
\(x\) = 94 - 25
\(x\) = 69
Vậy \(x\) = 69
a)-3/5.5/7+3/-5.3/7+3/5.-6/7
b)3/13:-11/-6+-3/13:11/-5-2/13
c)1/2.(x+2)+3/8=7/16
d)1/3x+2/5(x+1)=0
-1/3+5/2x=1/6:(-2/9)
a: \(=\dfrac{-3}{5}\cdot\dfrac{5}{7}+\dfrac{-3}{5}\cdot\dfrac{3}{7}+\dfrac{-3}{5}\cdot\dfrac{6}{7}\)
\(=\dfrac{-3}{5}\left(\dfrac{5}{7}+\dfrac{3}{7}+\dfrac{6}{7}\right)=\dfrac{-3}{5}\cdot2=-\dfrac{6}{5}\)
b: \(=\dfrac{3}{13}\cdot\dfrac{6}{11}+\dfrac{3}{13}\cdot\dfrac{5}{11}-\dfrac{2}{13}=\dfrac{3}{13}-\dfrac{2}{13}=\dfrac{1}{13}\)
c: =>1/2x+1+3/8=7/16
=>1/2x=-15/16
=>x=-15/8
d: =>5/2x-1/3=1/6*(-9)/2=-9/12=-3/4
=>5/2x=-3/4+1/3=-9/12+4/12=-5/12
=>x=-1/6
2)tìm x:
a)x-2/3=4/5.3/4
b)x-11/18=0,2+7/18
c)-3/8x+3/10=4/5
d)3/5+2/5x=1
2^5.6^7/8^5.3^5
X,y ti le thuan voi 2*5 va x-y=21
x,y ti le nghich voi 2:5 va x+2y=54
\(\frac{2^5\cdot6^7}{8^5\cdot3^5}=\frac{2^5\cdot\left(2\cdot3\right)^7}{\left(2\cdot4\right)^5\cdot3^5}=\frac{2^5\cdot2^7\cdot3^7}{2^5\cdot4^5\cdot3^5}=\frac{2^7\cdot3}{4^5}\)
x; y tỉ lệ thuận với 2 và 5 nên :
\(\frac{x}{2}=\frac{y}{5}\)
\(\Rightarrow\frac{x-y}{2-5}=\frac{x}{2}=\frac{y}{5}\) mà x - y = 21
\(\Rightarrow\frac{21}{-3}=\frac{x}{2}=\frac{y}{5}\)
\(\Rightarrow-7=\frac{x}{2}=\frac{y}{5}\)
\(\Rightarrow\hept{\begin{cases}x=-7\cdot2=-14\\y=-7\cdot5=-35\end{cases}}\)
vậy_
x; y tỉ lệ nghịch với 2 và 5 nên :
2x = 5y
=> 2x/10 = 5y/10
=> x/5 = y/2
=> x/5 = 2y/4
=> x + 2y/5 + 4 = x/5 = y/2 mà x + 2y = 54
=> 54/9 = x/5 = y/2
=> 6 = x/6 = y/2
=> x = 6*6 = 36; y = 6*2 = 12
vậy_
-3/4.4/7+-3/5.3/7+2/-5
47/53. ( 17/3 - 53/47) + 17/3 .( 6/17 - 47/53)
5/7 . ( 1/2 -1/3 +4/7 ) + ( 1/3 - 1/2 -4/7 ) :7/5
tim x
3 (x-1/2 ) - 5 ( x- 2/3) = 3/2x
help me mik dang can gap . cam on