Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Đề sai:
\(\frac{2018.2019-1000}{2018.2018+1018}\)
\(\Rightarrow\frac{2018.2018+2018-1000}{2018.2018+1018}\)
\(\Rightarrow\frac{2018.2018+1018}{2018.2018+1018}\)
\(=1\)
(-1) + 2 + (-3) + 4 + ... + (-2019) + 2020
= [ (-1) + 2 ] + [ (-3) + 4 ] + ... + [ (-2019) + 2020 ]
= 1 + 1 + ... + 1
= 1 . 1010
= 1010
(-1)+2+(-3)+4+...+(-2019)+2020
=(-1+2)+(-3+4)+...+(-2019+2020)
=1+1+...+1 (có 1010 số 1)
=1.1010
=1010
Bài 1:
0,5\(x\) - \(\dfrac{2}{3}\)\(x\) = \(\dfrac{7}{12}\)
\(\dfrac{1}{2}\)\(x\) - \(\dfrac{2}{3}x\) = \(\dfrac{7}{12}\)
(\(\dfrac{1}{2}-\dfrac{2}{3}\))\(x\) = \(\dfrac{7}{12}\)
- \(\dfrac{1}{6}\)\(x\) = \(\dfrac{7}{12}\)
\(x\) = \(\dfrac{7}{12}\) : (- \(\dfrac{1}{6}\))
\(x\) = - \(\dfrac{7}{2}\)
Vậy \(x\) = - \(\dfrac{7}{2}\)
a) 4.(1 930 + 2 019) + 4.(-2 019)
= 4.(1 930 + 2 019 - 2 019)
= 4.1 930
= 7 720
b) (-3).(-17) + 3.(120 - 17)
= 3.17 + 3.(120 - 17)
= 3.(17 + 120 - 17)
= 3.120
= 360
\(19.64+76.34\)
\(=19.64+19.4.34\)
\(=19.64+19.136\)
\(=19.\left(64+136\right)\)
\(=19.200\)
\(=3800\)
\(35.12+65.13\)
\(=5.7.12+5.13.13\)
\(=5.84+5.169\)
\(=5.\left(84+169\right)\)
\(=5.253\)
\(=1265\)
\(19991999.1998-19981998.1999\)
\(=1999.10101.1998-1998.10101.1999\)
\(=0\)
\(\left(2+4+6+......+100\right).\left(36.333-108.111\right)\)
\(=\left(2+4+6+........+100\right).\left(36.3.111-108.111\right)\)
\(=\left(2+4+6+........+100\right).\left(108.111-108.111\right)\)
\(=\left(2+4+6+.......+100\right).0\)
\(=0\)
19x64+76x34
=19x64+19x4x34
=19x(64+136)
=19x200=3800
35x12+65x13
=5x7x12+5x13x13
=5x(7x12+13x13)
=5x253=1265
19991999x1998-19981998x1999
=1999x10001x1999-1998x10001x1999
=0
( 2+4+6+... +100) x ( 36x 333 -108 x111)
=(2+4+6+...+100)x(36x111x3-36x3x111)
=(..................tự điền, như trên thôi)x0=0
4 x (1930 + 2019) + 4 x (-1019)
= 4 x (1930 + 2019 - 1019)
= 4 x [1930 + (2019 - 1019)]
= 4 x [1930 + 1000]
= 4 x 2930
= 11720
4x1930+4x(-1019)
=4x(1930-1019)
=4x911
=3644