( 2000 + 43 ) * 57 + ( 300 -57 ) * 43
nhanh giúp mk nha đang cần gấp
cảm ơn nhìu
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Bài 2:
1) \(x^2-4=x^2-2^2=\left(x-2\right)\left(x+2\right)\)
2) \(1-4x^2=1^2-\left(2x\right)^2=\left(1-2x\right)\left(1+2x\right)\)
3) \(4x^2-9=\left(2x\right)^2-3^2=\left(2x+3\right)\left(2x-3\right)\)
4) \(9-25x^2=3^2-\left(5x\right)^2=\left(3-5x\right)\left(3+5x\right)\)
5) \(4x^2-25=\left(2x\right)^2-5^2=\left(2x+5\right)\left(2x-5\right)\)
6) \(9x^2-36=\left(3x\right)^2-6^2=\left(3x-6\right)\left(3x+6\right)\)
7) \(\left(3x\right)^2-y^2=\left(3x-y\right)\left(3x+y\right)\)
8) \(x^2-\left(2y\right)^2=\left(x-2y\right)\left(x+2y\right)\)
9) \(\left(2x\right)^2-y^2=\left(2x-y\right)\left(2x+y\right)\)
10) \(\left(3x\right)^2-9y^4=\left(3x\right)^2-\left(3y^2\right)^2=\left(3x-3y^2\right)\left(3x+3y^2\right)\)
Bài 2:
21) \(\left(\dfrac{x}{3}-\dfrac{y}{4}\right)\left(\dfrac{x}{3}+\dfrac{y}{4}\right)=\left(\dfrac{x}{3}\right)^2-\left(\dfrac{y}{4}\right)^2=\dfrac{x^2}{9}-\dfrac{y^2}{16}\)
22) \(\left(\dfrac{x}{y}-\dfrac{2}{3}\right)\left(\dfrac{x}{y}+\dfrac{2}{3}\right)=\left(\dfrac{x}{y}\right)^2-\left(\dfrac{2}{3}\right)^2=\dfrac{x^2}{y^2}-\dfrac{4}{9}\)
23) \(\left(\dfrac{x}{2}+\dfrac{y}{3}\right)\left(\dfrac{x}{2}-\dfrac{y}{3}\right)=\left(\dfrac{x}{2}\right)^2-\left(\dfrac{y}{3}\right)^2=\dfrac{x^2}{4}-\dfrac{y^2}{9}\)
24) \(\left(2x-\dfrac{2}{3}\right)\left(\dfrac{2}{3}+2x\right)=\left(2x-\dfrac{2}{3}\right)\left(2x+\dfrac{2}{3}\right)=\left(2x\right)^2-\left(\dfrac{2}{3}\right)^2=4x^2-\dfrac{4}{9}\)
25) \(\left(2x+\dfrac{3}{5}\right)\left(\dfrac{3}{5}-2x\right)=\left(\dfrac{3}{5}+2x\right)\left(\dfrac{3}{5}-2x\right)=\left(\dfrac{3}{5}\right)^2-\left(2x\right)^2=\dfrac{9}{25}-4x^2\)
26) \(\left(\dfrac{1}{2}x-\dfrac{4}{3}\right)\left(\dfrac{4}{3}+\dfrac{1}{2}x\right)=\left(\dfrac{1}{2}x-\dfrac{4}{3}\right)\left(\dfrac{1}{2}x+\dfrac{4}{3}\right)=\left(\dfrac{1}{2}x\right)^2-\left(\dfrac{4}{3}\right)^2=\dfrac{1}{4}x^2-\dfrac{16}{9}\)
27) \(\left(\dfrac{2}{3}x^2-\dfrac{y}{2}\right)\left(\dfrac{2}{3}x^2+\dfrac{y}{2}\right)=\left(\dfrac{2}{3}x^2\right)^2-\left(\dfrac{y}{2}\right)^2=\dfrac{4}{9}x^4-\dfrac{y^2}{4}\)
28) \(\left(3x-y^2\right)\left(3x+y^2\right)=\left(3x\right)^2-\left(y^2\right)^2=9x^2-y^4\)
29) \(\left(x^2-2y\right)\left(x^2+2y\right)=\left(x^2\right)^2-\left(2y\right)^2=x^4-4y^2\)
30) \(\left(x^2-y^2\right)\left(x^2+y^2\right)=\left(x^2\right)^2-\left(y^2\right)^2=x^4-y^4\)
1.what do you think about the environment in your town?
In my hometown , people are not aware of environmental protection, there are still many people who are unaware and throw their garbage out, besides, there are still people who pick up trash and throw it in the right place.
Every day on the news reports, the news is everywhere, saying phrases like melting ice, global warming, acid rain, global climate change or adding new lands to become industrial landfills. All are consequences of environmental pollution.
(12-12)-(57-57) nhé, khi đổi chỗ các số thì bạn nên nhớ vẫn giữ nguyên dấu, còn chuyển vế mới đổi dấu nha
You can refer this one:
Recycle/Reuse Your Books. ...
Ditch the Paper. ...
Buy a Water Bottle. ...
Turn Off Your Phone. ...
Recycle. ...
Avoid Public Transport When Possible. ...
Save Water. ...
Save Electricity.
\(\dfrac{55}{57}< 1< \dfrac{89}{43}\)
\(\Rightarrow\dfrac{55}{57}< \dfrac{89}{43}\)
=57.(157-98-57):57 (bn đặt thừa số chung nhé)
=157-98-57=2 (sai thôi nhé mk ko bấm máy)
=\(=\frac{57\left(157-98-57\right)}{57}=2\)
bạn ơi! có hai cách ra hai kết quả khác nhau theo bạn cách nào là đúng?
( 42 x 43 + 43 x 57 + 43 ) - 360 : 4
= 43 x ( 42 + 57 + 1 ) - 90
= 43 x 100 - 90
= 4300 - 90
= 4210
a) \(=23.\left(1305-305\right)\)
\(=23.1000\)
\(=23000\)
b) \(=57.\left(84+15+1\right)\)
\(=57.100\)
\(=5700\)
a,1305x23-305x23
=(1305-305)x23
= 1000x23
= 23000
b,84x57+15x57+57
=84x57+15x57+57x1
=(84+15+1)x57
= 100x57
=5700
5017842
( 2000 + 43 ) x 57 + ( 300 - 57 ) x 43
= 2043 x 57 + 243 x 43
= 116451 + 10449
= 126900
tk mk tk lại