Giai phuong trinh:
\(x^4+\sqrt{x^2+3}=3\)
Giai phuong trinh:
\(28+\sqrt[3]{x^2}=3x+2\sqrt[3]{x}+\left(x-4\right)\sqrt{x-7}\)
giai phuong trinh :
\(\dfrac{\sqrt{x+3}+\sqrt{x-1}}{\sqrt{x+3}-\sqrt{x-1}}=\dfrac{13-x^2}{4}\)
\(\Leftrightarrow\dfrac{x+3+x-1+2\sqrt{\left(x+3\right)\left(x-1\right)}}{x+3-x+1}=\dfrac{13-x^2}{4}\)
\(\Leftrightarrow2x+2+2\sqrt{\left(x+3\right)\left(x-1\right)}=13-x^2\)
\(\Leftrightarrow\sqrt{4\left(x+3\right)\left(x-1\right)}=13-x^2-2x-2=-x^2-2x+11\)
=>\(x\simeq1,37\)
giai phuong trinh
\(2\sqrt[3]{\left(x+2\right)^2}-\sqrt[3]{\left(x-2\right)^2}=\sqrt[3]{x^2-4}\)
\(2\sqrt[3]{\left(x+2\right)^2}-\sqrt[3]{\left(x-2\right)^2}=\sqrt[3]{x^2-4}\)
\(\Leftrightarrow\sqrt[3]{\left(x-2\right)^2}=\sqrt[3]{x^2-4}\)
\(\Rightarrow\left(x-2\right)^2=x^2-4\)
\(\Leftrightarrow x^2-4x+4-x^2+4=0\)
\(\Leftrightarrow-4x+8=0\)
\(\Leftrightarrow x=2\)
Đặt \(\sqrt[3]{x+2}=a;\sqrt[3]{x-2}=b;\) ta có:
\(2a^2-b^2=ab\) ⇔ \(2a^2-ab-b^2=0\)
\(\Leftrightarrow2a^2+ab-2ab-b^2=0\)
⇔ \(\left(2a+b\right)\left(a-b\right)=0\)
⇔ \(\left[{}\begin{matrix}2\sqrt[3]{x+2}=-\sqrt[3]{x-2}\\\sqrt[3]{x-2}=\sqrt[3]{x+2}\end{matrix}\right.\)⇔ \(x=-\frac{14}{9}\)
giai phuong trinh
\(x^4-2\sqrt{3}x^2+x+3-\sqrt{3}\)=0
giai phuong trinh \(\sqrt[4]{x+1}+\sqrt[4]{1-x}+\sqrt[4]{1-x^2}=3\)
giai phuong trinh \(\sqrt{x\left(x-3\right)}-\sqrt{7x-3}=2\sqrt{x^2}\)
Giai phuong trinh
\(\sqrt{x-\sqrt{x-2}}+\sqrt{x+\sqrt{x-2}}=3\)
\(\sqrt{x-\sqrt{x-2}}+\sqrt{x+\sqrt{x-2}}=3\)
\(\Leftrightarrow2x+2\sqrt{\left(x-\sqrt{2-x}\right)\left(x+\sqrt{x-2}\right)}=9\)
\(\Leftrightarrow2\sqrt{\left(x-\sqrt{x-2}\right)\left(x+\sqrt{x+2}\right)}=9-2x\)
\(\Leftrightarrow4\left(x-\sqrt{x-2}\right)\left(x+\sqrt{x-2}\right)=\left(9-2x\right)^2\)
\(\Leftrightarrow4x^2-4x+8=81-36x+4x^2\)
\(\Leftrightarrow-4x+8=81-36x\)
\(\Leftrightarrow-4x=81-36x-8\)
\(\Leftrightarrow-4x=-36x+73\)
\(\Leftrightarrow-4x+36x=73\)
\(\Leftrightarrow32x=73\)
\(\Leftrightarrow x=\frac{73}{32}\)
Vậy: nghiệm phương trình là: \(\left\{\frac{73}{32}\right\}\)
Lỗi sai ngu người nhất của Chihiro.Quên viết ĐKXĐ ak em
\(\sqrt{x-\sqrt{x-2}}+\sqrt{x+\sqrt{x-2}}=3\)
\(ĐKXĐ:x\ge2\)
Bình phương 2 vế của pt ta được
\(2x+2\sqrt{\left(x-\sqrt{x-2}\right)\left(x+\sqrt{x-2}\right)}=9\)
\(\Leftrightarrow2\sqrt{x^2-x+2}=9-2x\)
\(\Leftrightarrow\hept{\begin{cases}9-2x\ge0\Leftrightarrow\frac{9}{2}\ge x\\4\left(x^2-x+2\right)=81-36x+4x^2\left(2\right)\end{cases}}\)
\(\left(2\right)\Leftrightarrow32x-73=0\Leftrightarrow x=\frac{73}{32}\left(tmDK\right)\)
Vậy \(S=\left\{\frac{73}{32}\right\}\)
p/s:học hỏi đi con.
Không thích thì không ghi được không ạ? :))
Giai phuong trinh va he phuong trinh:
a) \(\sqrt{x^2+6}=x-2\sqrt{x^2-1}\)
b) \(x^2+3x+1=\left(x+3\right).\sqrt{x^2+1}\)
c) \(\left\{{}\begin{matrix}x^2+y^2=11\\x+xy+y=3+4\sqrt{2}\end{matrix}\right.\)
Giai phuong trinh \(\sqrt{x^3+15}+2=\sqrt{x^3+8}+3x\)
Em đã thử liên hợp nhưng cái ngoặc to xấu xí quá:(