=(1975/1976+2010/2011+1963/1968)x(4/12-3/12-1/12)

=(1975/1976+2010/2011+1963/1968)x0

=0

Số số hạng của dãy là: \(\frac{40-12}{1}+1=40-12+1=41-12=29\) (số)

Tổng của dãy số là:

\(\left(40+12\right)\cdot\frac{29}{2}=52\cdot\frac{29}{2}=26\cdot29=754\)

oki

\(=\frac{16}{3}x\frac{30}{7}=\frac{480}{21}=\frac{160}{7}\)

\(\frac{33}{5}:\frac{21}{4}=\frac{33}{5}x\frac{4}{21}=\frac{132}{105}=\frac{44}{35}\)

a) \(5\frac{1}{3}.4\frac{2}{7}=\frac{16}{3}.\frac{30}{7}=\frac{160}{7}\)

b) \(6\frac{3}{5}:5\frac{1}{4}=\frac{33}{5}:\frac{21}{4}=\frac{33}{5}.\frac{4}{21}=\frac{44}{35}\)

\(\frac{9620}{979}\)

<br class="Apple-interchange-newline"><div></div>71.52+53530.71−180 ⇔52+53530−180 ⇔105350  (Lược các số giống nhau đi)

#)Giải :

Bài 1 :

\(A=\frac{15}{6.16}+\frac{15}{16.26}+\frac{15}{26.36}\)

\(A=3\left(\frac{5}{6.16}+\frac{5}{16.26}+\frac{5}{26.36}\right)\)

\(A=3\left(\frac{1}{6}-\frac{1}{16}+\frac{1}{16}-\frac{1}{26}+\frac{1}{26}-\frac{1}{36}\right)\)

\(A=3\left(\frac{1}{6}-\frac{1}{36}\right)\)

\(A=3.\frac{5}{36}\)

\(A=\frac{15}{36}\)

\(B=\frac{33}{6.16}-\frac{63}{16.26}+\frac{93}{26.36}\)

\(B=\frac{3.11}{6.16}-\frac{3.21}{16.26}+\frac{3.31}{26.36}\)

\(B=\frac{1}{2.16}.11+\frac{1}{2.16}.\frac{3.21}{13}+\frac{3.31}{26.36}\)

\(B=\frac{1}{32}.\frac{143-63}{13}+\frac{3.31}{26.12.3}\)

\(B=\frac{1}{32}.\frac{80}{13}+\frac{31}{36.12}\)

\(B=\frac{5}{26}+\frac{31}{26.12}=\frac{60+31}{26.12}=\frac{91}{26.12}=\frac{13.7}{13.2.12}=\frac{7}{24}\)

Bài 2 :

a)\(28.157-28.267+28.10\)

\(=28\left(157-267+10\right)\)

\(=28.-100\)

\(=-2800\)

b)\(\left(-5\right).4.\left(-2\right).23.\left(-25\right)\)

\(=\left[4.\left(-25\right)\right].\left[\left(-5\right).2\right].23\)

\(=\left(-100\right).\left(-10\right).23\)

\(=23000\)

2)

28 . 157  -  28 .267 + 28.10 

=28.( 157 - 267 + 10 )

= 28 . -100

= -2800

3)

[(-2).(-5)]. 4 .-25.23

= 10 . -100 .23

=-23000

còn câu 1 mik suy nghĩ đã

\(\frac{4^3.2^5.9^7}{2^5.27^2}=\frac{\left(2^2\right)^3.2^5.\left(3^2\right)^7}{2^5.\left(3^3\right)^2}=\frac{2^{11}.3^{14}}{2^5.3^6}=2^6.3^8\)

Bài làm :

\(\frac{4^3.2^5.9^7}{2^5.27^2}\)

\(=\frac{\left(2^2\right)^3.2^5.\left(3^2\right)^7}{2^5.\left(3^3\right)^2}\)

\(=\frac{2^6.3^{14}}{3^6}\)

\(=2^6.3^8\)

Học tốt

\(=\frac{33\cdot26\cdot36-63\cdot6\cdot36+93\cdot6\cdot16}{6\cdot16\cdot26\cdot36}\)

\(=\frac{30888-13608+8928}{89856}\)

\(=\frac{26208}{89856}=\frac{7}{24}\)

_Kik nha!! ^ ^

2.
a) (2x + 1)³ = 125
    (2x + 1)³ = 5³
     2x + 1    = 5
     2x          = 5 - 1
     2x          = 4
       x          = 4:2
       x          = 2
Vậy x = 2
b) 5^x+1 = 5⁴
    x + 1 = 4
    x       = 4 - 1 
    x       = 3
Vây x = 3

a) \(A=1.2+2.3+3.4+...+98.99+99.100\)

\(3A=1.2.3+2.3.4+3.4.3+...+99.100.3\) 

\(3A=1.2.\left(3-0\right)+2.3.\left(4-1\right)+3.4.\left(5-2\right)....99.100.\left(101-98\right)\) 

\(3A=\left(1.2.3+2.3.4+3.4.5+...+99.100.101\right)-\left(0.1.2+1.2.3+2.3.4+...+98.99.100\right)\)

\(3A=99.100.101-0.1.2\) 

\(3A=999900-0\)

\(3A=999900\)

\(A=999900:3\)

\(\Rightarrow A=333300\)