NHớ tick

7/1×5+7/5×9+7/9×13+7/13×17+7/17×21

=7/4×(4/1×5+4/5×9+4/9×13+4/13×17+4/17×21)

=7/4×(1−1/5+1/5−1/9+1/9−1/13+1/13−1/17+1/17−1/21)

=7/4×(1+0+0+0+0−1/21)

=7/4×(1−1/21)

=7/4×2021

=5/3

nhớ tick nha

1.Flamingo: hồng hạc
2.Elephant: con voi
3.Ox: bò (bò đực)
4.Fox: con cáo
5.Hawk: chim ưng
6.Chimpanzee: tinh tinh
7.Leopard: báo
8.Buffalo: trâu
9.Koala: gấu túi
10.Rhino: tê giác

.Tiger: hổ
 Crocodile: cá sấu

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How to lessen and stop WATER pollution in your community:

Some General Ways to Prevent Water Pollution

• If you can, pick up litter and garbage by hand, and take it to your personal garbage can before it travels into local waterways.
• Never put chemicals down the drain. Place them into your outside garbage can or take them to the local authorized center.
• Wash your car where the water and soap can go to a dirt or grass area instead of a street and drain to the river or creek.

my concert is more beautiful than a town concert

($x$ - 15)$\times$ 7 - 270 : 45 = 169

(�x - 15) $\times$ 7 - 6 = 169

(�x - 15) $\times$ 7 = 169 + 6

($x$ - 15) $\times$ 7 = 175

$x$ - 15 = 175 : 7

$x$ - 15 = 25

$x$        = 25 + 15

$x$       = 40