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6. We really her sense of humor.
7. He ought not to play computer games.
8. Hilary doesn't have to wear uniform at school.
IV. Viết lại câu với từ gợi ý .
6. We/ really / her/ sense/ humor.
................We really her sense of humor.......................................................................................................
7. He ought/ not/ play computer games.
...................He ought not to play computer games................................................................................................
8. Hilary/ not/ have to/ wear/ uniform / at school.
..................Hilary does not have to wear uniform at school.................................................................
\(\left(x^2+x\right)^2+4\left(x^2+x\right)-12\)
\(=\left(x^2+x\right)^2+2.\left(x^2+x\right).2+4-16\)
\(=\left(x^2+x+2\right)^2-4^2\)
\(=\left(x^2+x+2-4\right)\left(x^2+x+2+4\right)\)
\(=\left(x^2+x-2\right)\left(x^2+x+6\right)\)
\(P=\left(x^2+x\right)^2+4\left(x^2+x\right)-12\)
Đặt \(x^2+x=t\) Khi đó:
\(P=t^2+4t-12\)
\(=t^2+6t-2t-12\)
\(=t\left(t+6\right)-2\left(t+6\right)\)
\(=\left(t+6\right)\left(t-2\right)\)
\(=\left(x^2+x+6\right)\left(x^2+x-2\right)\)
\(=\left(x^2+x+6\right)\left[x\left(x+2\right)-\left(x+2\right)\right]\)
\(=\left(x^2+x+6\right)\left(x+2\right)\left(x-1\right)\)
\(x^4+3x^2-4\)
\(=x^4+4x^2-x^2-4\)
\(=x^2\left(x^2+4\right)-\left(x^2+4\right)\)
\(=\left(x^2+4\right)\left(x^2-1\right)\)
\(=\left(x^2+4\right)\left(x-1\right)\left(x+1\right)\)
Chúc bạn học tốt.
IV. Viết lại câu với từ gợi ý .
6. We/ really / her/ sense/ humor.
.......................We really her sense of humor............................................................................................
7. He ought/ not/ play computer games.
..........He ought not to play computer games......................................................................................
8. Hilary/ not/ have to/ wear/ uniform / at school.
..........Hilary does not have to wear uniform at school...................................................................
ta có: ab(a + b) + bc(b + c) + ac(a + c) + 3abc
= ab(a + b) + abc + bc(b + c) + abc + ac(a + c) + abc
= ab(a + b + c) + bc(a + b + c) + ac(a + b + c)
= (a + b + c)(ab + bc + ca)
ab(a+b) + bc(b+c) + ca(c+a) = a^2b + ab^2 + b^2c + bc^2 + ca(c+a) + 2abc
= ab^2 + b^2c + a^2b + bc^2 + 2abc + ca(c+a)
=b^2(a+c) + b(a^2 + c^2 + 2ac) + ca(c+a)
=b^2(a+c) + b(a+c)^2 + ca(c+a)
=(c+a)[b^2 + b(a+c) + ca]
=(c+a)[b^2 + ab + bc + ca]
=(c+a)[b(b+a) + c(b+a)]
=(c+a)(b+c)(b+a)
TRẢ LỜI GIÚP MÌNH VỚI MINH ĐANG RẤT GẤP CÓ AI HỌC THẦY CẢNH KO LỚP 7 SÁCH HỌC TỐT TÙ BÀI 96 ĐẾN BAIF113 HÌNH
Bài làm
Each summer vacation, I am taken to the countryside by my parents so as to relax after a hard working term. I really the life here. In rural areas, there are not as many houses and vehicles as in the city. As the result, the atmosphere is quite fresh and cool. Most people mainly travel by bicycle or on foot. The landscape is very poe and picturesque. There are many gardens, rivers here. We can grow vegetables or chickens, fish,... on our own. The local are very kind, generous and friendly. They are willing to give directions to strangers and help each other in difficult times. Whenever we are away, we can relievedly ask our neighbors to keep our houses and children . Another thing that we especially is that in the countryside, we are reconciled to nature so that the soul is always open and the body is healthy. Living in the countryside is fun and wonderful. In the future, I really want to live here.
a ) K hóa trị I
b) NO3 hóa trị I ( Ba hóa trị II )
c) Fe hóa trị II
d) N hóa trị I
e) N hóa trị IV
f) ....
g) Al hóa trị III ( Al2(SO4)3
a, Gọi hóa trị của K trong \(K_2SO_4\)là x
Theo qui tắc hóa trị, ta có:
\(x.2=1.II\)
\(\Rightarrow x=I\)
Vậy K trong K2SO4 có hóa trị I
Tương tự với các ý còn lại.
b, Bạn viết sai rồi Ba hóa trị 2 mà.
c, Fe (I)
d, N (I)
e, N (IV)
f, làm gì có NO2
g, Bạn viết sai CTHH rồi.