1.

`16 + (27 - 7.6 ) - (94 -7 - 27.99)`

`= 16+ 27 - 7.6 - 94 + 7 + 27.99`

`= 16 + 27(99 +1) - 7(6-1) - 94`

`= -78 + 27.100 - 7.5`

`= 2587`

2.

`A = 2/1.4 + 2/4.7 + 2/7.10 +...+ 2/97.100`

`A= 2(1/1.4 + 1/4.7 + 1/7.10 +...+1/97.100)`

`3A = 2 (3/1.4 + 3/4.7 + 3/7.10+...+ 3/97.100)`

`3/2 A = 1 - 1/4 + 1/4 - 1/7 +...+ 1/97 - 1/100`

`3/2A = 1 - 1/100`

`3/2 A= 99/100`

`A= 99/100 : 3/2`

`A=33/50`

Vậy `A= 33/50`

1.16+(27-7.6)-(94-7-27.99)=16+27-7.6-94+7+27.99

                                           =(27+27.99)+(27+7-94)+16

                                           =27.100-60+16

                                           =2700-44=2656

2.A=\(\dfrac{2}{1.4}+\dfrac{2}{4.7}+\dfrac{2}{7.10}+...+\dfrac{2}{97.100}\)

     =\(\dfrac{1}{1}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+...+\dfrac{1}{97}-\dfrac{1}{100}\)

     =\(1-\dfrac{1}{100}=\dfrac{99}{100}\)

1) \(16+\left(27-7.6\right)-\left(94-7-27.99\right)\)

=\(16+27-7.6-94+7+27.99\)

=\(\left(27+27.99\right)+\left(-7.6+7\right)+\left(16-94\right)\)

=\(27\left(1+99\right)+7\left(-6+1\right)-78\)

=\(27.100-7.5-78=2700-35-78=2587\).

2) \(A=\dfrac{2}{1.4}+\dfrac{2}{4.7}+\dfrac{2}{7.10}+...+\dfrac{2}{97.100}\)

\(A=\dfrac{2.3}{1.4.3}+\dfrac{2.3}{4.7.3}+\dfrac{2.3}{7.10.3}+...+\dfrac{2.3}{97.100.3}\)

\(A=\dfrac{2}{3}.\left(\dfrac{3}{1.4}+\dfrac{3}{4.7}+\dfrac{3}{7.10}+...+\dfrac{3}{97.100}\right)\)

\(A=\dfrac{2}{3}.\left(\dfrac{1}{1}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{10}+...+\dfrac{1}{97}-\dfrac{1}{100}\right)\)

\(A=\dfrac{2}{3}.\left(\dfrac{1}{1}-\dfrac{1}{100}\right)=\dfrac{2}{3}.\dfrac{99}{100}=\dfrac{33}{50}\)

Mình tính ra là 2023.Có ai có ý kiến không ?

what the heo my

mình ra 2023 có ai ra 2023 ko

ai có thì để lại cho mik 1 cái tích đúng nha

cảm ơn các bạn

Bài 1 :

\(S=1.3+3.5+5.7+...+99.101=3+15+35+...9999\)

Ta thấy :

\(3=2^2-1\)

\(15=4^2-1\)

\(35=6^2-1\)

.....

\(9999=100^2-1\)

\(\Rightarrow S=2^2+4^2+...+100^2-\left(1\right).\left(\left(100-2\right):2+1\right)\)

\(\Rightarrow S=\dfrac{100.\left(100+1\right)\left(2.100+1\right)}{6}-51\)

\(\Rightarrow S=\dfrac{100.101.201}{6}-51=338299\)

nhanh len nhé mik đang cần gấp ai lam trước mik tích cho

Bài 6 :

\(C=1^2+2^2+...+100^2=\dfrac{100.\left(100+1\right)\left(2.100+1\right)}{6}=\dfrac{100.101.201}{6}=338350\)

Bài 9 :

\(S=1^2+2^2+3^2+...+99^2=\dfrac{99.\left(99+1\right)\left(2.99+1\right)}{6}=\dfrac{99.100.199}{6}=328350\)

16+(27-7.6)-94.7-27.99

=16+27-7.6-94.7-27.99

16+27(1+99)-7(6+94)=+2700-700=2016

đúng thì tk cho mk nha

2016 nha ban

Đáp án là 2016 bạn nha

2003² - 2002.2003

= 2003.(2003 - 2002)

= 2003 . 1

= 2003

-------------------

7(x - 2) + 2³ = 2.5²

7(x - 2) + 8 = 2.25

7(x - 2) = 50 - 8

7(x - 2) = 42

x - 2 = 42 : 7

x - 2 = 6

x = 6 + 2

x = 8

-------------------

23 + (27 - 7.6) - (94.7 - 27.99)

= 23 + 27 - 42 - 658 + 2673

= 23 + (27 + 2673) - (42 + 658)

= 23 + 2700 - 700

= 23 + 2000

= 2023

`2023^2-2022.2023`

`=2023.2023-2022.2023`

`=2023.(2023-2022)`

`=2023.1`

`=2023`

__

` 23 + (27 - 7.6) - (94.7 - 27.99)`

` = 23 + (27 - 42) - (658 - 2673)`

` = 23 + (-15) - (-2015)`

` = 8 + 2015`

` = 2023`

\(2023^2-2022.2023\)

\(=2023\left(2023-2022\right)\)

\(=2023.1\)

\(=2023\)

\(23+\left(27-7.6\right)-\left(94.7-27.99\right)\)

\(=23+27-7.6-94.7+27.99\)

\(=23+\left(27+27.99\right)-\left(7.6+94.7\right)\)

\(=23+27\left(1+99\right)-7.\left(6+94\right)\)

\(=23+27.100-7.100\)

\(=23+2000\)

\(=2023\)

a) \(16+\left(27-7\cdot6\right)-\left(94\cdot7-27\cdot99\right)\)

\(=16+27-7\cdot6-94\cdot7+27\cdot99\)

\(=16+27\left(1+99\right)-7\left(6+94\right)=16+2700-700=2016\)

b)\(A=\frac{2}{1\cdot4}+\frac{2}{4\cdot7}+\frac{2}{7\cdot10}+...+\frac{2}{97\cdot100}\)

\(=\frac{1}{3}\left(\frac{2}{1}-\frac{2}{4}+\frac{2}{4}-\frac{2}{7}+\frac{2}{7}-\frac{2}{10}+...+\frac{2}{97}-\frac{2}{100}\right)\)

\(=\frac{1}{3}\left(2-\frac{2}{100}\right)=\frac{1}{3}\cdot\frac{99}{50}=\frac{33}{50}\)

\(=\frac{32+16+8+4+2+1}{64}=\frac{63}{64}\)