Giúp mình với các bạn , anh @Nguyễn Lê Phước Thịnh
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bạn ghi rõ nội dung, yêu cầu đề của bài đó ra cho mình nha
b) Ta có: \(\left(-\dfrac{1}{2}\right)^2\cdot2\dfrac{6}{7}-\dfrac{14}{15}:2\dfrac{1}{3}+\left(-1.21\right)^0\)
\(=\dfrac{1}{4}\cdot\dfrac{20}{7}-\dfrac{14}{15}:\dfrac{7}{3}+1\)
\(=\dfrac{5}{7}-\dfrac{14}{15}\cdot\dfrac{3}{7}+1\)
\(=\dfrac{5}{7}-\dfrac{2}{5}+1\)
\(=\dfrac{25-14-35}{35}=\dfrac{-24}{35}\)
\(B=\dfrac{2x+3\sqrt{x}+9}{x-9}-\dfrac{\sqrt{x}}{\sqrt{x}+3}\)
\(\Rightarrow B=\dfrac{2x+3\sqrt{x}+9}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}-\dfrac{\sqrt{x}\left(\sqrt{x}-3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)
\(\Rightarrow B=\dfrac{2x+3\sqrt{x}+9}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}-\dfrac{x-3\sqrt{x}}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)
\(\Rightarrow B=\dfrac{2x+3\sqrt{x}+9-x+3\sqrt{x}}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)
\(\Rightarrow B=\dfrac{x+6\sqrt{x}+9}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)
\(\Rightarrow B=\dfrac{\left(\sqrt{x}+3\right)^2}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}\)
\(\Rightarrow B=\dfrac{\sqrt{x}+3}{\sqrt{x}-3}\)
\(\dfrac{2x+3\sqrt{x}+9-\sqrt{x}\left(\sqrt{x}-3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\dfrac{\left(\sqrt{x}+3\right)^2}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=\dfrac{\sqrt{x}+3}{\sqrt{x}-3}\)
b: \(\Leftrightarrow n+1\in\left\{1;-1;2;-2;4;-4\right\}\)
hay \(n\in\left\{0;-2;1;-3;3;-5\right\}\)
c: \(\Leftrightarrow n+2\in\left\{1;-1;5;-5\right\}\)
hay \(n\in\left\{-1;-3;3;-7\right\}\)
d: \(\Leftrightarrow n+2\in\left\{1;-1;2;-2;4;-4\right\}\)
hay \(n\in\left\{-1;-3;0;-4;2;-6\right\}\)
a: \(\Leftrightarrow n-1\in\left\{1;-1;5;-5\right\}\)
hay \(n\in\left\{2;0;6;-4\right\}\)
\(=\dfrac{1}{2}\cdot\dfrac{2}{3}\cdot\dfrac{3}{4}\cdot...\cdot\dfrac{2021}{2022}\cdot\dfrac{2022}{2023}\)
=1/2023
\(B=\dfrac{1}{2}.\dfrac{2}{3}.\dfrac{3}{4}...\dfrac{2021}{2022}.\dfrac{2022}{2023}\)
\(=\dfrac{1.2.3...2022}{2.3.4...2023}=\dfrac{1}{2023}\)
Du la fan cua ai di chang nua,Online Math nay cung khong phai la cai khu cua cac cau thich lam gi thi lam.Day la khu hoc!!!!
a)
const fo='bt4_20.pas';
var f:text;
a,b,c,s,xx:longint;
begin
assign(f,fo); rewrite(f);
a:=30000;
b:=a*2;
c:=b-10000;
s:=a+b+c;
xx:=9500;
writeln(f,s div xx);
close(f);
end.
b)
const fo='bt4_20c2.pas';
var f:text;
a,b,c,s,xx:longint;
begin
assign(f,fo); rewrite(f);
a:=30000;
b:=a*2;
c:=b-10000;
s:=a+b+c;
xx:=9500;
writeln(f,s/xx:4:0);
close(f);
end.
khai báo rồi mà