tìm x biết
a) (3x-1)2 - (x+3)3 = (2-x) (x2 + 2x +4)
b) ( x +1)(x2 +1) (x-1) - (x2 - 1)2 = 2
c) x2 - 2\(\sqrt{3x}\) + 3 = 0
d) ( x- \(\sqrt{2}\) ) ( x + \(\sqrt{2}\) ) - ( x - \(\sqrt{2}\) ) 2 = 0
e) (2x-3)2 - (3x-2)2= 0
f)...
Đọc tiếp
tìm x biết
a) (3x-1)2 - (x+3)3 = (2-x) (x2 + 2x +4)
b) ( x +1)(x2 +1) (x-1) - (x2 - 1)2 = 2
c) x2 - 2\(\sqrt{3x}\) + 3 = 0
d) ( x- \(\sqrt{2}\) ) ( x + \(\sqrt{2}\) ) - ( x - \(\sqrt{2}\) ) 2 = 0
e) (2x-3)2 - (3x-2)2= 0
f) \(\dfrac{3}{4}\left(2x+1\right)^2-\dfrac{1}{3}=0\)
Bài 1.
a: \(\left(3x-1\right)^2-\left(x+3\right)^3=\left(2-x\right)\left(x^2+2x+4\right)\)
\(\Leftrightarrow9x^2-6x+1-x^3-9x^2-27x-27=8-x^3\)
\(\Leftrightarrow-x^3-33x-26-8+x^3=0\)
=>-33x=34
hay x=-34/33
b: \(\left(x+1\right)\left(x-1\right)\left(x^2+1\right)-\left(x^2-1\right)^2=2\)
\(\Leftrightarrow\left(x^2+1\right)\left(x^2-1\right)-\left(x^2-1\right)^2=2\)
\(\Leftrightarrow x^4-1-x^4+2x^2-1=2\)
\(\Leftrightarrow2x^2=4\)
hay \(x\in\left\{\sqrt{2};-\sqrt{2}\right\}\)
c: \(x^2-2\sqrt{3}x+3=0\)
\(\Leftrightarrow\left(x-\sqrt{3}\right)^2=0\)
hay \(x=\sqrt{3}\)
d: \(\left(x-\sqrt{2}\right)\left(x+\sqrt{2}\right)-\left(x-\sqrt{2}\right)^2=0\)
\(\Leftrightarrow\left(x-\sqrt{2}\right)\left(x+\sqrt{2}-x+\sqrt{2}\right)=0\)
\(\Leftrightarrow x-\sqrt{2}=0\)
hay \(x=\sqrt{2}\)