2 góc phụ nhau `<=>` Chúng có tổng bằng `90^o`.

`=>` Góc còn lại là: `90^o-30^o=60^o`

`=>` A.

a) `(2x-21) . 2/3 = -90`

`3x-21=-135`

`3x=-114`

`x=-38`

b) `(2x-30) . 2/3 = -30`

`2x-30=-45`

`2x=-15`

`x=-15/2`.

TH1: `-1+|3x-2| >=0 <=> |3x-2| >=1`

TH1.1: `3x-2>=0 <=> x >= 2/3`

`-1+3x-2>4`

`<=>3x>7`

`<=>x>7/3`

Vậy `x>7/3`

TH1.2: `3x-2<0 <=> x <3/2`

`-1-3x+2>4`

`<=> -3x>3`

`<=>x<-1`

Vậy `x<-1`

TH2: `-1+|3x-2|<0 <=> |3x-2|<1`

TH2.1: `3x-2>=0 <=> x >= 2/3`

`1-3x+2>4`

`<=>-3x>1`

`<=>x<-1/3`

`=>` VN.

TH2.2: `3x-2<0 <=> x<2/3`

`1+3x-2>4`

`<=>2x>5`

`<=>x>5/2`

`=>` VN.

Vậy `S=(-∞ ; -1) \vee (7/3 ; + ∞)`.

- Vâng, em cảm ơn ạ.

- Chụp thiếu rồi bạn ơi...

33. Were he not afraid of height, he would come climbing.

34. They prevented the boy from getting in the disco because he was under 18. 

35.What do you call a man who studies Biology ?

36. Bill reminded Susan about buy some sugar.

37. We have a thirty-minute break.

38. What is your date of birth ?

39. The last time I have been in Laichau was in February.

40. Despite being old/her age, she tries to climb the mountain very often.

- Chỗ S:=S+i sửa thành S:=S+A[i] nkaaa.

Vậy \(V=28m^3\) nkaa. =(((

PTBĐ: tự sự, miêu tả.

program im_14424;

uses crt;

var A: array[1..1000000] of longint;

S: longint;

i: integer;

begin

clrscr;

write('Nhap vao n: ');

readln(n);

S:=0;

for i:=1 to n do

begin

write('Nhap phan tu thu`,i,':');

readln(A[i]);

S:=S+i;

end;

readln

end.