96*(7^2+1)*(7^4+1)*(7^8+1)*(7^16+1)
Giúp mình nhá :D
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a: \(=\dfrac{6}{7}:\dfrac{12}{35}=\dfrac{6}{7}\cdot\dfrac{35}{12}=\dfrac{6}{12}\cdot\dfrac{35}{7}=\dfrac{5}{2}\)
b: \(=\dfrac{6}{7}+\dfrac{1}{7}-\dfrac{8}{9}=1-\dfrac{8}{9}=\dfrac{1}{9}\)
c: \(=\dfrac{6}{7}+\dfrac{1}{8}-\dfrac{3}{4}=\dfrac{6}{7}-\dfrac{5}{8}=\dfrac{48-35}{56}=\dfrac{13}{56}\)
`a)`
`(105/31-31/202+104/91)xx(1/2-1/3-1/6)`
`=(105/31-31/202+104/91)xx(3/6-2/6-1/6)`
`=(105/31-31/202+104/91)xx0/6`
`=(105/31-31/202+104/91)xx0`
`=0`
`b)`
`6/7:(2/5xx6/7)`
`=6/7:2/5xx6/7`
`=(6/7:6/7):2/5`
`=1:2/5`
`=5/2`
`c)`
`6/7 + 5/7 : 5 - 8/9`
`=6/7+1/7-8/9`
`=9/9-8/9`
`=1/9`
`d)`
`6/7 + 5/8 . 1/5 - 3/16 .4`
`=6/7+1/8-3/4`
`=(48+7-12)/56`
`=13/56`
`@Nae`
1) ta có \(\left(x+y\right)^2=x^2+2xy+y^2.\)
\(=\left(x^2+y^2\right)+2xy\)
\(=20+2.8\)(theo giả thiết x^2+y^2=20 , xy=8)
\(=36\)
Vậy với x^2+y^2=20, xy=8 thì (x+y)^2=36
2) \(M=\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(\Rightarrow3M=3\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left[\left(2^2\right)^2-1^2\right]\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left[\left(2^4\right)^2-1^2\right]\left(2^8+1\right)\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left(2^8-1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left[\left(2^8\right)^2-1^2\right]\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left(2^{16}-1\right)\left(2^{16}+1\right)\)
\(\Leftrightarrow3M=\left(2^{16}\right)^2-1^2\)
\(\Leftrightarrow3M=2^{32}-1\)
\(\Rightarrow M=\frac{2^{32}-1}{3}\)
RÚT GỌN BIỂU THỨC N BẠN LÀM TƯƠNG TỰ NHA
\(N=16\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\left(7^{16}+1\right)\)
\(\Rightarrow3N=48\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\left(7^{16}+1\right)\)
\(\Leftrightarrow3N=\left(7^2-1\right)\left(7^2+1\right)\left(7^4+1\right)\left(7^8+1\right)\left(7^{16}+1\right)\)
\(...\)
\(...\)
Kết quả rút gọn \(N=\frac{7^{32}-1}{3}\)
a) 1/2 + 3/4 - (3/4 - 4 - 5)
= 1/2 + 3/4 - 3/4 + 4 + 5
= (3/4 - 3/4) + (4 + 5) + 1/2
= 0 + 9 + 1/2
= 19/2
b) [9/16 + 8/(-27)] - (19/27- 7/16 - 2)
= 9/16 - 8/27 - 19/27 + 7/16 + 2
= (9/16 + 7/16) + (-8/27 - 19/27) + 2
= 1 - 1 + 2
= 2
c) -5/8 . [4/9 + 7/(-12)]
= -5/8 . (-5/36)
= 25/288
d) 7/10 . (-3/5) + 7/10 . (-2/5) - (-3/10)
= 7/10 . (-3/5 - 2/5) + 3/10
= 7/10 . (-1) + 3/10
= -2/5
e) -3/7 . 5/9 + 4/9 . (-3/7) + 2 3/7
= -3/7 . (5/9 + 4/9) + 17/7
= -3/7 . 1 + 17/7
= 2
f) 8 2/7 - (3 4/9 + 4 2/7)
= 8 + 2/7 - 3 - 4/9 - 4 - 2/7
= (8 - 3 - 4) + (2/7 - 2/7) - 4/9
= 1 - 4/9
= 5/9
h) 3.(-1/2)² - (4/5 + 8/15) : 5/6
= 3.1/4 - 4/3 : 5/6
= 3/4 - 8/5
= -17/20
1)\(\dfrac{2}{9}+\dfrac{-3}{4}+\dfrac{5}{30}\)
\(=\dfrac{2.20}{9.20}+\dfrac{-3.45}{4.45}+\dfrac{5.6}{30.6}\)
\(=\dfrac{40}{180}+\dfrac{-135}{180}+\dfrac{30}{180}\)
\(=\dfrac{40+\left(-135\right)+30}{180}\)
\(=\dfrac{-65}{180}\)
\(=\dfrac{-13}{36}\)
2)\(\dfrac{-7}{12}-\dfrac{11}{18}\)
\(=\dfrac{-7.3}{12.3}-\dfrac{11.2}{18.2}\)
\(=\dfrac{-21}{36}-\dfrac{22}{36}\)
\(=\dfrac{-21-22}{36}\)
\(=\dfrac{-43}{36}\)
3)\(\dfrac{7}{8}-\dfrac{-5}{16}\)
\(=\dfrac{7.2}{8.2}-\dfrac{-5}{16}\)
\(=\dfrac{14}{16}-\dfrac{-5}{16}\)
\(=\dfrac{14-\left(-5\right)}{16}\)
\(=\dfrac{19}{16}\)
4)\(\dfrac{3}{8}-\dfrac{-9}{10}-\dfrac{5}{16}\)
\(=\dfrac{3.10}{8.10}-\dfrac{-9.8}{10.8}-\dfrac{5.5}{16.5}\)
\(=\dfrac{30}{80}-\dfrac{-72}{80}-\dfrac{25}{80}\)
\(=\dfrac{30-\left(-72\right)-25}{80}\)
\(=\dfrac{77}{80}\)
\(a.\frac{1}{7}\times\frac{-3}{8}+\frac{-13}{8}==\frac{-3}{56}+\frac{-13}{8}=\frac{-3}{56}+\frac{-91}{56}=\frac{-94}{56}=\frac{-47}{28}\)
\(b.\frac{3}{5}\times\frac{13}{40}-\frac{1}{10}\times\frac{16}{23}=\frac{39}{200}-\frac{8}{115}=\frac{577}{4600}\)
\(c.\left(\frac{-3}{4}+\frac{2}{5}\right):\frac{3}{7}+\left(\frac{3}{5}+\frac{1}{4}\right):\frac{3}{7}\)
\(=\left(\frac{-3}{4}+\frac{2}{5}\right)\times\frac{7}{3}+\left(\frac{3}{5}+\frac{1}{4}\right)\times\frac{7}{3}\)
\(=\frac{7}{3}\times\left(\frac{-3}{4}+\frac{2}{5}+\frac{3}{5}+\frac{1}{4}\right)\)
\(=\frac{7}{3}\times\left[\left(\frac{-3}{4}+\frac{1}{4}\right)+\left(\frac{2}{5}+\frac{3}{5}\right)\right]\)
\(=\frac{7}{3}\times\left(\frac{-2}{4}+1\right)\)
\(=\frac{7}{3}\times\frac{1}{2}\)
\(=\frac{7}{6}\)
\(d.\frac{7}{8}:\left(\frac{2}{9}-\frac{1}{8}\right)+\frac{7}{8}:\left(\frac{1}{6}-\frac{5}{12}\right)\)
\(=\frac{7}{8}:\frac{7}{72}+\frac{7}{8}:\left(\frac{-1}{4}\right)\)
\(=\frac{7}{8}\times\frac{72}{7}+\frac{7}{8}\times-4\)
\(=\frac{7}{8}\times\left(\frac{72}{7}+\left(-4\right)\right)\)
\(=\frac{7}{8}\times\frac{44}{7}\)
\(=\frac{11}{2}\)
B1:
A.1+1=2
B.6+2+5=13
C.6+4+6+2+7=25
D.6+4+7+8=25
B2:
A.x+2=3
x=3-2
x=1
B.x+5=4+6
x+5=10
x=10-5
x=5
C.7=4+x
x=7-4
x=3
D.4+x={3+5+7}+{3+5}
4+x=15+8
4+x=23
x=23-4
x=19
Bài 1 :
A.1+1=2
B.6+2+5=13
C.6+4+6+2+7=25
D.6+4+7+8=25
Bài 2 :
A.x+2=3
x=3-2
x=1
B.x+5=4+6
x+5=10
x=10-5
x=5
C.7=4+x
x=7-4
x=3
D.4+x={3+5+7}+{3+5}
4+x=15+8
4+x=23
x=23-4
x=19
Chúc bạn học tốt nha ~_~
Câu 1 :
a, 8.( -5 ).( -4 ).2
= [ 8.2 ].[( -5 ).(-4 ]
= 16.20
= 320
b, \(1\frac{3}{7}+\frac{-1}{3}+2\frac{4}{7}\)
\(=\frac{10}{7}+\frac{-1}{3}+\frac{18}{7}\)
\(=\frac{11}{3}\)
c, \(\frac{8}{5}.\frac{2}{3}+\frac{-5.5}{3.5}\)
\(=\frac{8}{3}+\frac{-5}{3}\)
\(=\frac{3}{3}=1\)
d, \(\frac{6}{7}+\frac{5}{8}:5-\frac{3}{16}.\left(-2\right)^2\)
\(=\frac{6}{7}+\frac{1}{8}-\frac{3}{16}.4\)
\(=\frac{55}{56}-\frac{3}{4}\)
\(=\frac{13}{56}\)
Câu 2 :
a, 2x + 10 = 16
2x = 16 + 10
2x = 26
x = 26 : 2
x = 13
b, \(x-\frac{1}{3}=\frac{5}{4}\)
\(x=\frac{5}{4}+\frac{1}{3}\)
\(x=\frac{19}{12}\)
c, \(2x+3\frac{1}{3}=7\frac{1}{3}\)
\(2x+\frac{10}{3}=\frac{22}{3}\)
\(2x=\frac{22}{3}-\frac{10}{3}\)
\(2x=4\)
\(x=4:2\)
\(x=2\)
d, \(\left(\frac{2}{11}+\frac{1}{3}\right)x=\left(\frac{1}{7}-\frac{1}{8}\right).56\)
\(\frac{17}{33}x=1\)
\(x=1-\frac{17}{33}\)
\(x=\frac{16}{33}\)
1) \(-1,6:\left(1+\frac{8}{12}\right)\)
\(=-1,6:\left(1+\frac{2}{3}\right)\)
\(=-1,6:1-1,6:\frac{2}{3}\)
\(=-1,6+\frac{-1,6.3}{2}\)
\(=-1,6-2,4\)
\(=4\)
2) \(\frac{3}{8}-\frac{4}{5}-\frac{-17}{40}\)
\(=\frac{15-32+17}{40}\)
=0
3) \(\frac{3}{4}-\frac{16}{32}+\frac{4}{-3}\)
\(=\frac{3}{4}-\frac{2}{4}+\frac{-4}{3}\)
\(=\frac{9-6-16}{12}\)
\(=\frac{-13}{12}\)
4) \(\frac{-4}{7}+\frac{2}{3}.\frac{-9}{14}\)
\(=\frac{-4}{7}+\frac{-3}{7}=-1\)
5) \(2\frac{3}{4}-\left(\frac{1}{7}+1\frac{3}{4}\right)\)
\(=\frac{11}{4}-\left(\frac{1}{7}+\frac{7}{4}\right)\)
\(=\frac{11}{4}-\frac{4+49}{28}\)
\(=\frac{11}{4}-\frac{53}{28}\)
\(=\frac{77-53}{28}=\frac{24}{28}=\frac{6}{7}\)
6) \(8\frac{2}{7}-\left(3\frac{4}{9}+4\frac{2}{7}\right)\)
\(=\frac{58}{7}-\left(\frac{31}{9}+\frac{30}{7}\right)=\frac{522-217+270}{63}\)
\(=\frac{575}{63}\)
`96.(7^{2}+1).(7^{4}+1).(7^{8}+1).(7^{16}+1)`
`=2.(7^{2}-1).(7^{2}+1).(7^{4}+1).(7^{8}+1).(7^{16}+1)`
`=2.(7^{4}-1).(7^{4}+1).(7^{8}+1).(7^{16}+1)`
`=2.(7^{8}-1).(7^{8}+1).(7^{16}+1)`
`=2.(7^{16}-1).(7^{16}+1)`
`=2.(7^{32}-1)`