Giai phuong trinh :\(\sqrt{2-x^2+2x}+\sqrt{-x^2-6x+8}=1+\sqrt{3}\)
giai phuong trinh: \(\sqrt{2x^2-1}+\sqrt{x^2-3x-2}=\sqrt{2x^2+2x+3}+\sqrt{x^2-x-1}\)
giai phuong trinh \(\sqrt{\frac{x+7}{x+1}}+8=2x^2+\sqrt{2x-1}\)
ĐKXĐ: \(x\ge\frac{1}{2}\)
Đề \(\Rightarrow\sqrt{\frac{x+7}{x+1}}-\sqrt{3}+8-2x^2-\left(\sqrt{2x-1}-\sqrt{3}\right)=0\)
Nhân liên hợp ta được:
\(\frac{\left(\sqrt{\frac{x+7}{x+1}}-\sqrt{3}\right)\left(\sqrt{\frac{x+7}{x+1}}+\sqrt{3}\right)}{\sqrt{\frac{x+7}{x+1}}+\sqrt{3}}+2\left(4-x^2\right)-\frac{\left(\sqrt{2x-1}-\sqrt{3}\right)\left(\sqrt{2x+1}+\sqrt{3}\right)}{\sqrt{2x+1}+\sqrt{3}}=0\)
\(\Rightarrow\frac{\frac{x+7}{x+1}-3}{\sqrt{\frac{x+7}{x+1}}+\sqrt{3}}+2\left(4-x^2\right)-\frac{2x-1-3}{\sqrt{2x+1}+\sqrt{3}}=0\)
\(\Rightarrow\frac{\frac{-2x+4}{x+1}}{\sqrt{\frac{x+7}{x+1}}+\sqrt{3}}+2\left(2-x\right)\left(2+x\right)-\frac{2x-4}{\sqrt{2x+1}+\sqrt{3}}=0\)
\(\Rightarrow\left(x-2\right)\left[\frac{-2}{\left(x+1\right)\left(\sqrt{\frac{x+7}{x+1}}+\sqrt{3}\right)}-2\left(2+x\right)-\frac{2}{\sqrt{2x+1}+\sqrt{3}}\right]=0\)
mà \(-\frac{2}{\left(x+1\right)\left(\sqrt{\frac{x+7}{x+1}}+\sqrt{3}\right)}-2\left(2+x\right)-\frac{2}{\sqrt{2x+1}+\sqrt{3}}< 0\)
=> x - 2 = 0 => x = 2
Vậy x = 2
Giai phuong trinh
\(\sqrt{x+2+3\sqrt{2x-5}}+\sqrt{x-2-2\sqrt{2x-5}}=2\sqrt{2}\)
Giai phuong trinh sau:
\(\sqrt{x^2-6x+9}+\sqrt{x^2+10x+25}=8\)
ta có đề bài <=>
\(\sqrt{\left(x-3\right)^2}+\sqrt{\left(x+5\right)^2}=8\)
<=> \(\left|x-3\right|+\left|x+5\right|=8\)
<=>\(\left|3-x\right|+\left|x+5\right|=8\)
Áp dụng tính chât dấu giá trị tuyệt đối ta có
\(\left|3-x\right|+\left|x+5\right|>=\left|3-x+x+5\right|=8\)
dấu = xảy ra <=> \(\left(3-x\right)\left(x+5\right)>=0\)
đến đây bạn tự giaỉ dấu = nhé
giai phuong trinh : \(2x^2\left(5-\sqrt[3]{5x-x^3}\right)=2x^3+17x-8\)
Giai phuong trinh ; 2\(\sqrt{x^2-x}-2\sqrt{x}\sqrt{2x-1}+3x=1\)
\(\sqrt{x+2+3\sqrt{ }2x-5}+\sqrt{x-2-\sqrt{ }2x-5}=2\sqrt{2}\) 2\(\sqrt{2}\) giai phuong trinh
giai phuong trinh: \(\sqrt[3]{x^2+4x+3}+\sqrt[3]{4x^2-9x-3}=\sqrt[3]{3x^2-2x+2}+\sqrt[3]{2x^2-3x-2}\)
Giai phuong trinh \(\sqrt{2x^2+8x+6}+\sqrt{x^2-1}=2x+2\)
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