\(\left(x^2+7\right)+4x=\left(x+4\right)\sqrt{x^2+7}\)
ĐẶt :\(\sqrt{x^2+7}\) = a > 0
=> a2 - (x+4)a +4x=0 =>\(\Delta=\left(x+4\right)^2-16x=\left(x-4\right)^2\ge0\)
a = \(\frac{x+4+\left|x-4\right|}{2}\Leftrightarrow\int^{a=x}_{a=4}\)
+a =x =>\(\sqrt{x^2+7}\)= x vô nghiệm
+ a =4 => \(\sqrt{x^2+7}\)=4 => x2 = 9 => x =3 ; x = -3
giải pt:
a) \(4\sqrt{x-2}+\sqrt{9x-18}-\sqrt{\dfrac{x-2}{4}}=26\)
b) \(3x+\sqrt{4x^2-8x+4}=1\)
c) \(\left(2\sqrt{x}+1\right)\left(\sqrt{x}-2\right)=7\)
giúp mk vs ạ mk cần gấp
giải pt \(x^2+4x+7=\left(x+4\right)\sqrt{x^2+7}\)
giải pt \(6\left(x^2+x+1\right)^2+2x^2+2x-3-\sqrt{4x+5}=0\)
\(\sqrt{2x^2+4x+7}=x^4+4x^3+3x^2-2x-7\)
giải hệ: \(\left\{{}\begin{matrix}\dfrac{1}{x-y}+\dfrac{1}{x+y}=2\\\dfrac{2}{x+y}+\dfrac{3}{x+y}=5\end{matrix}\right.\)
giải pt: \(\sqrt{x^2-4x+7}=\sqrt{x+1}\)
giải PT
\(x^2+4x-7=\left(x+4\right)\sqrt{x^2-7}\)
mình đang cần gấp . giúp mình nha
Giải phương trình:
a) \(\sqrt{4-3x}=8\)
b) \(\sqrt{4x-8}-12\sqrt{\dfrac{x-2}{9}}=-1\)
c) \(\left(2\sqrt{x}+1\right)\left(\sqrt{x}-2\right)=7\)
giải phương trình:
a, \(x+4\sqrt{7-x}=4\sqrt{x-1}+\sqrt{\left(7-x\right)\left(x-1\right)}+1\)
b, \(x^2+2x+4=3\sqrt{x^2+4x}\)
Giải hpt sau:
a)\(\left\{{}\begin{matrix}2\left(x^2-2x\right)+\sqrt{y+1}=0\\3\left(x^2-2x\right)-2\sqrt{y+1}+7=0\end{matrix}\right.\)
b)\(\left\{{}\begin{matrix}5\left|x-1\right|-3\left|y+2\right|=7\\2\sqrt{4x^2-8x+4}+5\sqrt{y^2+4y+4}=13\end{matrix}\right.\)
c)\(\left\{{}\begin{matrix}\dfrac{3x}{x+1}-\dfrac{2}{y+4}=4\\\dfrac{2x}{x+1}-\dfrac{5}{y+4}=9\end{matrix}\right.\)
d)\(\left\{{}\begin{matrix}\dfrac{x+1}{x-1}+\dfrac{3y}{y+2}=7\\\dfrac{2}{x-1}-\dfrac{5}{y+2}=4\end{matrix}\right.\)
2. Giải PT:
a) \(\frac{9x-7}{\sqrt{7x+5}}=\sqrt{7x+5}.\)
b) \(\sqrt{4x-20}+3\sqrt{\frac{x-5}{9}}-\frac{1}{3}\sqrt{9x-45}=4.\)
c) \(2x-x^2+\sqrt{6x^2-12x+7}=0.\)
d) \(\left(x+1\right)\left(x+4\right)-3\sqrt{x^2+5x+2}=6.\)
