\(P=\left(x^2+2x\right)\left(y^2-4y\right)+5\left(x^2+2x\right)+4\left(y^2-4y\right)+2021\)

\(=\left[\left(x+1\right)^2-1\right]\left[\left(y-2\right)^2-4\right]+5\left(x+1\right)^2+4\left(y-2\right)^2+2000\)

\(=\left(x+1\right)^2\left(y-2\right)^2+\left(x+1\right)^2+3\left(y-2\right)^2+2024\ge2024\)

\(P_{min}=2024\) khi \(\left(x;y\right)=\left(-1;2\right)\)

Chọn D

Lỗi ạ

uses crt;

var st:string;

d,i:integer;

begin

clrscr;

readln(st);

d:=length(st);

for i:=1 to d do 

  if (st[i] in ['0'..'9']) then write(st[i]);

readln;

end.

Bài 1.19:

d: A=[-3;3]

B(-4;1)

\(A\cap B\)=[-3;1)

\(A\cup B=\)(-4;3]

(Bạn tự làm GTKL nhé)

a, Ta có:

AB ⊥ p (gt)

p // q (gt)   

=> AB ⊥ q ( từ ⊥ đến // )

b, Ta có : C₂ + D₁ = 180^o ( TCP )

=> C₂ = 180^o - D₁

          = 180^o - 70^o

          = 110^o

  Vậy C₂ = 110^o.