x 3 /4 = 5 /2
12 /27 - x =2 /9
4/5 * x = 9 /7
31 /29 / x = 9/7
\(\dfrac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^{29}\cdot9^{10}-7\cdot2^{29}\cdot27^6}\)
\(=\dfrac{5\cdot2^{30}\cdot3^{18}-2^2\cdot2^{27}\cdot3^{20}}{5\cdot2^{29}\cdot3^{20}-7\cdot2^{29}\cdot3^{18}}\)
\(=\dfrac{2^{29}\cdot3^{18}\left(5\cdot2-3^2\right)}{2^{29}\cdot3^{18}\left(5\cdot3^2-7\right)}\)
\(=\dfrac{10-9}{5\cdot9-7}=\dfrac{1}{38}\)
Tính A= 5 x 4^15 x 9^9 - 4 x 3^20 x 8^9 : 5 x 2^9 x 6^19 - 7 x 2^29 x 27^6
B= {[ 5 * (2^2)^15 * (3^2)^9 ] - [ (2^2) * 3^20 * (2^3)^9 ]} / {[ 5 * (2^9) * (2^19)*(3^19) ] - [ 7 * (2^29) * (3^3)^6 ]}
B= {[ 5 * (2^30) * (3^18) ] - [ (3^20) * (2^29) ]} / {[ 5 * (2^28) * (3^19) ] - [ 7 * (2^29) * (3^18) ]}
B= {[ (2^29) * (3^18) ] * [(5 * 2) - 3^2 ]} / {[ (2^28) * (3^18) ] - [(5 * 3) - (7 * 2)] }
B= [ (2^29) * (3^18) ] / [ (2^28) * (3^18) ]
B= [ (2^1) * (2^28) * (3^18) ] / [ (2^28) * (3^18) ]
B = 2
dấu * là dấu nhân
B= {[ 5 * (2^2)^15 * (3^2)^9 ] - [ (2^2) * 3^20 * (2^3)^9 ]} / {[ 5 * (2^9) * (2^19)*(3^19) ] - [ 7 * (2^29) * (3^3)^6 ]}
B= {[ 5 * (2^30) * (3^18) ] - [ (3^20) * (2^29) ]} / {[ 5 * (2^28) * (3^19) ] - [ 7 * (2^29) * (3^18) ]}
B= {[ (2^29) * (3^18) ] * [(5 * 2) - 3^2 ]} / {[ (2^28) * (3^18) ] - [(5 * 3) - (7 * 2)] }
B= [ (2^29) * (3^18) ] / [ (2^28) * (3^18) ]
B= [ (2^1) * (2^28) * (3^18) ] / [ (2^28) * (3^18) ]
B = 2
dấu * là dấu nhân
B= 5 x 2 mũ 9x 6 mũ 19 -7 x 2 mũ 29 x 27 mũ 6
rồi tính A:B
\(A=5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9\)
\(A=5\cdot\left(2^2\right)^{15}\cdot\left(3^2\right)^9-2^2\cdot3^{20}\cdot\left(2^3\right)^9\)
\(A=5\cdot2^{30}\cdot3^{18}-2^2\cdot3^{20}\cdot2^{27}\)
\(A=5\cdot2^{30}\cdot3^{18}-2^{29}\cdot3^{20}\)
\(A=2^{29}\cdot3^{18}\cdot\left(5\cdot2^1\cdot1-1\cdot3^2\right)\)
\(A=2^{29}\cdot3^{18}\cdot\left(5-9\right)\)
\(A=-2^2\cdot2^{29}\cdot3^{18}\)
\(A=-2^{31}\cdot3^{18}\)
_______________
\(B=5\cdot2^9\cdot6^{19}-7\cdot2^{29}\cdot27^6\)
\(B=5\cdot2^9\cdot2^{19}\cdot3^{19}-7\cdot2^{29}\cdot\left(3^3\right)^6\)
\(B=5\cdot2^{28}\cdot3^{19}-7\cdot2^{29}\cdot3^{18}\)
\(B=2^{28}\cdot3^{18}\cdot\left(5\cdot1\cdot3-7\cdot2\cdot1\right)\)
\(B=2^{28}\cdot3^{18}\cdot\left(15-14\right)\)
\(B=2^{28}\cdot3^{18}\)
Ta có: \(A:B\)
\(=\left(-2^{31}\cdot3^{18}\right):\left(2^{28}\cdot3^{18}\right)\)
\(=\left(-2^{31}:2^{28}\right)\cdot\left(3^{18}:3^{18}\right)\)
\(=-2^3\cdot1\)
\(=-8\)
Thay các số mũ:
4=224 = 2^2 nên 415=(22)15=2304^{15} = (2^2)^{15} = 2^{30} 9=329 = 3^2 nên 99=(32)9=3189^9 = (3^2)^9 = 3^{18} 8=238 = 2^3 nên 89=(23)9=2278^9 = (2^3)^9 = 2^{27}Thay vào biểu thức:
A=5⋅230⋅318−4⋅320⋅227A = 5 \cdot 2^{30} \cdot 3^{18} - 4 \cdot 3^{20} \cdot 2^{27}Rút gọn:
A=5⋅230⋅318−4⋅320⋅227A = 5 \cdot 2^{30} \cdot 3^{18} - 4 \cdot 3^{20} \cdot 2^{27} =227⋅(5⋅23⋅318−4⋅320)= 2^{27} \cdot \left(5 \cdot 2^3 \cdot 3^{18} - 4 \cdot 3^{20}\right) =227⋅(40⋅318−4⋅320)= 2^{27} \cdot \left(40 \cdot 3^{18} - 4 \cdot 3^{20}\right) =227⋅4⋅318⋅(10−32)=4⋅227⋅318⋅1=4⋅227⋅318= 2^{27} \cdot 4 \cdot 3^{18} \cdot (10 - 3^2) = 4 \cdot 2^{27} \cdot 3^{18} \cdot 1 = 4 \cdot 2^{27} \cdot 3^{18} Tính BCho B=5⋅29⋅619−7⋅229⋅276B = 5 \cdot 2^{9} \cdot 6^{19} - 7 \cdot 2^{29} \cdot 27^{6}
Thay các số mũ:
6=2⋅36 = 2 \cdot 3, nên 619=219⋅3196^{19} = 2^{19} \cdot 3^{19} 27=3327 = 3^3, nên 276=(33)6=31827^6 = (3^3)^6 = 3^{18}Thay vào biểu thức:
B=5⋅29⋅(219⋅319)−7⋅229⋅318B = 5 \cdot 2^{9} \cdot (2^{19} \cdot 3^{19}) - 7 \cdot 2^{29} \cdot 3^{18} =5⋅228⋅319−7⋅229⋅318= 5 \cdot 2^{28} \cdot 3^{19} - 7 \cdot 2^{29} \cdot 3^{18}Rút gọn:
=228⋅318⋅(5⋅3−7⋅2)=228⋅318⋅(15−14)=228⋅318⋅1=228⋅318= 2^{28} \cdot 3^{18} \cdot (5 \cdot 3 - 7 \cdot 2) = 2^{28} \cdot 3^{18} \cdot (15 - 14) = 2^{28} \cdot 3^{18} \cdot 1 = 2^{28} \cdot 3^{18} Tính ABây giờ, chúng ta có:
A=4⋅227⋅318A = 4 \cdot 2^{27} \cdot 3^{18} B=228⋅318B = 2^{28} \cdot 3^{18}Tính tỉ số A:BA:B:
AB=4⋅227⋅318228⋅318=4⋅227228=42=2\frac{A}{B} = \frac{4 \cdot 2^{27} \cdot 3^{18}}{2^{28} \cdot 3^{18}} = \frac{4 \cdot 2^{27}}{2^{28}} = \frac{4}{2} = 2
Vậy A:B=2A:B = 2.
a,( x - 29 ) - ( 17 - 38 ) = -9
b, ( x + 5) + ( x - 9 ) = x + 2
c, ( 27 - x ) + ( 15 + x ) = x- 24
d, |2x - 7|- 9 =20
e, x^2 - 2x + 4 = -2x + 7
g, ( x + 1) + (x + 3) + ( x + 5 +...+ ( x + 99) = 0
a,( x - 29 ) - ( 17 - 38 ) = -9
( x - 29 ) + 21 = - 9
x - 29 = - 9 - 21
x - 29 = - 30
x = -30 + 29
x = -1
c, ( 27 - x ) + ( 15 + x ) = - 24
27 - x + 15 + x = -24
- x + x = -24-27-15
Vô lí vì 0 ko bằng -66
Vậy \(x\in\varnothing\)
d, |2x - 7|- 9 =20
|2x-7|=11
* 2x-7=11 * 2x-7=-11
2x=11+7 2x=-11+7
2x=18 2x=-4
x=18:2 x=-4:2
x=9 x=-2
Vậy x=9 hoặc x=-2
b, ( x + 5) + ( x - 9 ) = x + 2
b)(x+5)+(x-9)=x+2
x+5+x-9=x+2
x+x-x=2-5+9
x=6
Vậy x=6
B = 5 x 4^15 x 9^9 - 4 x 3^20 x 8^9 / 5 x 2^9 x 6^19 - 7 x 2^29 x 27^6
Bạn hãy rút gọn biểu thức trên ! ( hoặc tính luôn cũng được )
Giúp mình với mình đang cần gấp !
1. 27/5 x 91/12 x 125/9 x 96/13
2. 2539/35 x 7/90 + 561/35 x 7/90
3. 31/7 : (2/5 x 31/7)
4. (29 x 15/23 x 36/29) : 5/23
5. 4/3 x 5/4 x 6/5 x ... x 12/11
6. 34/11 x 27/46 x 23/17 x 22/9
7. 4/3 x 9/8 x 16/15 x 25/24 x ... x 100/99
a)\(\frac{27}{5}\text{x}\frac{91}{12}\text{x}\frac{125}{9}\text{x}\frac{96}{13}=\frac{27}{9}\text{x}\frac{91}{13}\text{x}\frac{125}{5}\text{x}\frac{96}{12}=3\text{x}7\text{x}25\text{x}8\)
Đến đây tự tính nha !
b)\(\frac{2539}{35}\text{x}\frac{7}{90}+\frac{561}{35}\text{x}\frac{7}{90}=\frac{7}{90}\text{x}\left(\frac{2539}{35}+\frac{561}{35}\right)=\frac{7}{90}\text{x}\frac{3100}{35}=\frac{3100}{90}\text{x}\frac{7}{35}=\frac{310}{9}\text{x}\frac{1}{5}=\frac{62}{9}\)
1. 27/5 x 91/12 x 125/9 x 96/13
2. 2539/35 x 7/90 + 561/35 x 7/90
3. 31/7 : (2/5 x 31/7)
4. (29 x 15/23 x 36/29) : 5/23
3)\(\dfrac{31}{7}\) : (\(\dfrac{2}{5}\times\dfrac{31}{7}\) )
=\(\dfrac{31}{7}\) : \(\dfrac{2}{5}\times\dfrac{31}{7}\)
= \(\dfrac{31}{7}:\dfrac{31}{7}\times\dfrac{2}{5}\)
= \(\dfrac{2}{5}\)
4) (\(29\times\dfrac{15}{23}\times\dfrac{31}{7}\)) : \(\dfrac{5}{23}\)
=\(29\times\dfrac{15}{23}\times\dfrac{31}{7}:\dfrac{5}{23}\)
= \(29\times\dfrac{31}{7}\times\dfrac{15}{23}:\dfrac{5}{23}\)
= 29 x \(\dfrac{31}{7}\times\dfrac{15}{23}\times\dfrac{23}{5}\)
= 29 x \(\dfrac{31}{7}\times3\)
= 29 x 3 x \(\dfrac{31}{7}\)
= 87 x \(\dfrac{31}{7}\)
= \(\dfrac{2697}{7}\)
1. -2/9 x 15/17 + -2/9 x 2/17
2. -5/3 x 6/5 + -7/9 x 3/10
3. 15/20 x 7/5 + -9/7 x -6/4
4.-25/13 x 5/19 + -25/13 x 14/19
5 -7/13 x 13/5 + -9/7 x 5/3
6. 27/35 x 5/9 - 2/7 x -7/5
7. 10/13 x 13/5 + {-9/5} x 10/3
8. 100/27 x 9/20 + 40% x 5/3
9. 1,5 x 5/12 + 1/4 x 3/4
10. 2 1/2 x 7/5 + {-9/10} x 2/3
11. X + 45% = 2 1/2 -5/3
12. 80% + X = -5/2 + 3/4
13. 4/25 - X =-5/2 + -3/10
1: =-2/9(15/17+2/17)=-2/9
2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)
=-2-7/30=-67/30
3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
1: =-2/9(15/17+2/17)=-2/9
2: =34⋅75+97⋅32=34⋅75+97⋅32
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
Bài 1:
1)-7/9x2 3/4
2)2/3+1/3x-2/5
3) 3/4 x 15 1/3 - 3/4 x 43 1/3
4) (-49,1)x 13/27 - 58,9 x 13/27
5) 0,375 : (-4,5)
6) 3 1/7 :( -1 3/7)
7) 9 1/3 :4 2/3 - 2
8) ( 7 3/4 : 0,3125 + 4,5 x2 2/45) : (-8,5)
Bài 2
A= (-6/11) x 7/10 x (11/-6) x(-20)
B= (-1/9) x (-17/29) x 58/51
C=(-3/7) x 5/11 +(-5/14)x5/11
D=(1 1/27 x 12/23 x 9/14 ) :(-3/23)
Bài 3 tìm x
a) 3/7x -2/5 x+-17/33
b)(3/4 x - 9/16).(1/3 +-3/5 : x)=0
c)(x+3/5 ) . (x+1)<0
(Hạn thứ 3 nha , giúp mk vs)
6. 27/35 x 5/9 - 2/7 x -7/5
7. 10/13 x 13/5 + {-9/5} x 10/3
8. 100/27 x 9/20 + 40% x 5/3
9. 1,5 x 5/12 + 1/4 x 3/4
9: =3/2*5/12+3/16
=15/24+3/16
=5/8+3/16
=13/16