GPT: \(5\left(\sqrt{x+5}+\sqrt{3x+4}\right)=5x^2-11x-1\)
gpt : a. \(x^2-7x=6\sqrt{x+5}-30\)
b. \(\sqrt{3x^2-5x+1}-\sqrt{x^2-2}=\sqrt{3\left(x^2-x-1\right)}-\sqrt{x^2-3x-4}\)
a) Điều kiện $x \ge -5$. Đặt $\sqrt{x+5}=a$ thì $x=a^2-5$. Thay vào ta có $$\begin{array}{l} (a^2-5)^2-7(a^2-5)=6a-30 \\ \Leftrightarrow a^4-17a^2-6a+90=0 \Leftrightarrow (a^2+6a+10)(a-3)^2=0 \end{array}$$
Vậy $a=3 \Leftrightarrow \boxed{ x= 4}$.
gpt:\(\sqrt{3x^2+6x+4}+\sqrt{2x^2+4x+11}=\left(1-x\right)\left(x+3\right)\)
\(\sqrt{3x^2+6x+7}+\sqrt{5x^2+10x+21}=5-x^2-2x\)
\(\sqrt{x^2-x+2}+\sqrt{x^2-3x+6}=2x\)
Giai các bất phương trình sau đây :
a/ \(\sqrt{\left(x-3\right)\left(8-x\right)}+26>-x^2+11x\)
b/ \(\left(x+5\right)\left(x-2\right)+3\sqrt{x\left(x+3\right)}>0\)
c/ \(\left(x+1\right)\left(x+4\right)< 5\sqrt{x^2+5x+28}\)
d/ \(\sqrt{3x^2+5x+7}-\sqrt{3x^2+5x+2}\ge1\)
HELP ME !!!!!!
1)\(7\sqrt{3x-7}+\left(4x-7\right)\sqrt{7-x}=32\)
2)\(4x^2-11x+6=\left(x-1\right)\sqrt{2x^2-6x+6}\)
3)\(9+3\sqrt{x\left(3-2x\right)}=7\sqrt{x}+5\sqrt{3-2x}\)
4)\(\sqrt{2x^2+4x+7}=x^4+4x^3+3x^2-2x-7\)
5)\(\frac{6-2x}{\sqrt{5-x}}+\frac{6+2x}{\sqrt{5+x}}=\frac{8}{3}\)
6)\(2\left(5x-3\right)\sqrt{x+1}+\left(x+1\right)\sqrt{3-x}=3\left(5x+1\right)\)
7)\(\sqrt{7x+7}+\sqrt{7x-6}+2\sqrt{49x^2+7x-42}=181-14x\)
giải phương trình :
a, \(\sqrt{x+1}+x+3=\sqrt{1-x}+3\sqrt{1-x^2}\)
b,\(\left(2x-3\right)\sqrt{3+x}+2x\sqrt{3-x}=6x-8+\sqrt{9-x^2}\)
c, \(2x^2-5x+22=5\sqrt{x^3-11x +20}\)
d, \(x^3-3x^2+2\sqrt{\left(x+2\right)^3}=6x\)
GPT: \(\log_2\left(\sqrt{x^2-5x+5}+1\right)+\log_3\left(x^2-5x+7\right)=2\)
Đặt \(\sqrt{x^2-5x+5}=t>0\)
\(\Rightarrow log_2\left(t+1\right)+log_3\left(t^2+2\right)-2=0\)
Nhận thấy \(t=1\) là 1 nghiệm của pt
Xét hàm \(f\left(t\right)=log_2\left(t+1\right)+log_3\left(t^2+2\right)-2\)
\(f'\left(t\right)=\dfrac{1}{\left(t+1\right)ln2}+\dfrac{2t}{\left(t^2+2\right)ln3}>0\Rightarrow f\left(t\right)\) đồng biến
\(\Rightarrow f\left(t\right)\) có tối đa 1 nghiệm
\(\Rightarrow t=1\) là nghiệm duy nhất của pt
\(\Rightarrow\sqrt{x^2-5x+5}=1\Rightarrow\left[{}\begin{matrix}x=1\\x=4\end{matrix}\right.\)
gpt:
\(3\left(x^2-3x+1\right)+\sqrt{3\left(x^4+x^2+1\right)}=0\)
\(\sqrt[3]{x^3+5x^2}-1=\sqrt{\frac{5x^2-2}{6}}\)
GPT: \(2\left(x-3\right)\sqrt{x^3+3x^2+x+3}+2\sqrt{x+1}=2x^3-11x^2+29x-38\)
a) \(\sqrt{3x^2-4x-4}\) =\(\sqrt{2x+5}\)
b) \(\sqrt{\left(x-3\right)\left(8-x\right)}+26=-x^2+11x\)
ĐK: \(x\ge-\dfrac{5}{2}\)
\(\Leftrightarrow3x^2-4x-4=2x+5\)
\(\Leftrightarrow3x^2-6x-9=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=3\end{matrix}\right.\) (thỏa mãn)
b.
ĐKXĐ: \(3\le x\le8\)
\(\Leftrightarrow-x^2+11x-24-\sqrt{-x^2+11x-24}-2=0\)
Đặt \(\sqrt{-x^2+11x-24}=t\ge0\)
\(\Rightarrow t^2-t-2=0\Rightarrow\left[{}\begin{matrix}t=-1\left(loại\right)\\t=2\end{matrix}\right.\)
\(\Leftrightarrow\sqrt{-x^2+11x-24}=2\)
\(\Leftrightarrow-x^2+11x-28=0\Rightarrow\left[{}\begin{matrix}x=7\\x=4\end{matrix}\right.\)