For years, comcem has been(1)........ by parents and teachers about the effect of computer games on the moral(2)....... make up of the next(3)........ Some have warned that a relentless diet of whiz bang 'shoot em up' foster anticipate behavior,(4).......playground violence.(5)........believe that the age of the zoombie is upon us.
But expert opinion is(6)........ radically. Psychologists in America and Britain now suggest that(7)........ coputer games hold some dangers for children, they also provide opportunities their parents(8)........enjoyed to ampilify powers of concentration memory. reseachers(9)........ also highlighted the positive(10)........of children to the way computer games reward such thereby spurring(11)......... on to look for greater challenges a boon if the same attitude is applied to school(12).......
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\(\sqrt{27-12\sqrt{5}}\)
\(=\sqrt{15-2\cdot\sqrt{36}\cdot\sqrt{5}+12}\)
\(=\sqrt{15-2\cdot\sqrt{15}\cdot\sqrt{12}+12}\)
\(=\sqrt{\left(\sqrt{15}-\sqrt{12}\right)^2}\)
\(=\sqrt{15}-\sqrt{12}\)
đây là ảnh của chủ câu hỏi này k phải tui đâu nha !
ĐK: \(x\ge1\)
\(\sqrt{x^2+x+1}+\sqrt{x-1}=\sqrt{x^3-1}+1\)
Đặt: \(a=\sqrt{x^2+x+1};\) \(b=\sqrt{x-1}\)Ta có:
\(a+b=ab+1\)
\(\Leftrightarrow\)\(\left(a-1\right)\left(b-1\right)=0\)
\(\Leftrightarrow\)\(\orbr{\begin{cases}a=1\\b=1\end{cases}}\)
Nếu: \(a=1\)thì: \(\sqrt{x^2+x+1}=1\)\(\Rightarrow\)\(x^2+x+1=1\)
\(\Leftrightarrow\)\(x\left(x+1\right)=0\) \(\Leftrightarrow\)\(\orbr{\begin{cases}x=0\\x=-1\end{cases}\left(L\right)}\)
Nếu: \(b=1\)thì: \(\sqrt{x-1}=1\)\(\Rightarrow\)\(x-1=1\)\(\Leftrightarrow\)\(x=2\) (t/m)
Vậy...
a/\(\sqrt{54}=3\sqrt{6}\)
b/\(\sqrt{50a}=\sqrt{50}.\sqrt{a}=5\sqrt{2}.\sqrt{a}\)
c/ \(\sqrt{5\left(\sqrt{3}\right)^2=}\sqrt{5.3}=\sqrt{15}\)
a) \(\sqrt{54}=\sqrt{9.6}=\sqrt{9}.\sqrt{6}=3\sqrt{6}\)
b) \(\sqrt{50a}=\sqrt{25.2a}=\sqrt{5^2.2a}=5\sqrt{2a}\)
Concem không có nghĩa