Lời giải:
a)
$x^3-6x^2-9x+14=0$
$\Leftrightarrow x^3-x^2-5x^2+5x-14x+14=0$
$\Leftrightarrow x^2(x-1)-5x(x-1)-14(x-1)=0$
$\Leftrightarrow (x-1)(x^2-5x-14)=0$
$\Leftrightarrow (x-1)(x^2-7x+2x-14)=0$
$\Leftrightarrow (x-1)[x(x-7)+2(x-7)]=0$
$\Leftrightarrow (x-1)(x+2)(x-7)=0$
$\Rightarrow x=1; x=-2$ hoặc $x=7$
b)
Bạn tham khảo tại đây:
Câu hỏi của Lương Đức Hưng - Toán lớp 8 | Học trực tuyến
Giải phương trình:
\(\dfrac{\left(2009-x\right)^2+\left(2009-x\right)\left(x-2010\right)+\left(x-2010\right)^2}{\left(2009-x\right)^2-\left(2009-x\right)\left(x-2010\right)+\left(x-2010\right)^2}=\dfrac{19}{49}\)
cho M= \(\dfrac{x^2}{\left(x+y\right)\left(1-y\right)}\)-\(\dfrac{y^2}{\left(x+y\right)\left(1+x\right)}\)-\(\dfrac{X^2y^2}{\left(1+x\right)\left(1-y\right)}\)
a, rút gọn M
b, tìm các cặp số nguyên x,y để biểu thức có giá trị là -2010
Giải các PT sau :
a,\(\frac{1-6x}{x-2}+\frac{9x+4}{x+2}=\frac{x\left(3x-2\right)+1}{\left(x+2\right)\left(x-2\right)}\)
b,(2 - 3x) (x + 11) = (3x - 2) (2 - 5x)
c,\(\frac{3x-2}{6}-5=\frac{3-2\left(x+7\right)}{4}\)
d,\(\frac{x}{x-3}+\frac{x}{x +1}=\frac{2x}{\left(x+1\right)\left(x-3\right)}\)
e,\(\frac{x+1}{5}+\frac{x+2}{4}=\frac{x+3}{3}+\frac{x+4}{2}\)
Giải phương trình
a) \(2x\left(x+5\right)=\left(x+3\right)^2+\left(x-1\right)^2+20\)
b) \(\left(2x-2\right)^3=\left(x+1\right)^2+3\left(x-2\right)\left(x+5\right)\)
c) \(\left(x-1\right)^2+\left(x+3\right)^2=2\left(x-2\right)\left(x+1\right)+38\)
d) \(\left(x+2\right)^3-\left(x-2\right)^3=12x\left(x-2\right)-8\)
a) \(8\left(x+\dfrac{1}{x}\right)^2+4\left(x^2+\dfrac{1}{x^2}\right)^2-4\left(x^2+\dfrac{1}{x^2}\right)\left(x+\dfrac{1}{x}\right)^2=\left(x+4\right)^2\)
b) \(\left(6x+7\right)^2\left(3x+4\right)\left(x+1\right)=6\)
c) \(\left(x+1\right)\left(x+2\right)\left(x+3\right)\left(x+4\right)=840\)
Giải phương trình:
\(8\left(x+\frac{1}{x}\right)^2+4\left(x^2+\frac{1}{x^2}\right)^2-4\left(x^2+\frac{1}{x^2}\right)\left(x+\frac{1}{x}\right)^2=\left(x+4\right)^2\)
Các chế ơi, còn 10 câu nữa thui, sắp hết rùi.
FIGHTING!
JIAYOU!
HWAITING!
GAMBATTEYO!
Giải các phương trình sau
16) \(3\left(x+5\right)\left(x+6\right)\left(x+7\right)=8x\)
17) \(\left(x+6\right)^4+\left(x+4\right)^4=82\)
18) \(\left(x^2+6x+10\right)^2+\left(x+3\right)\left(3x^2+20x+36\right)=0\)
19) \(2\left(x^2+x+1\right)^2-7\left(x-1\right)^2=13\left(x^3-1\right)\)
20) \(\left(x+2008\right)^4+\left(x+2009\right)^4=\dfrac{1}{8}\)
21) \(x^4+18x=13x^2+5\)
22) \(\dfrac{1}{5x^2}+\dfrac{1}{x^2-9x+36}=\dfrac{1}{x^2-4x+16}\)
23) \(\dfrac{\left(x+1\right)^2}{x^2+2x+2}-\dfrac{x^2+2x}{\left(x+1\right)^2}=\dfrac{1}{90}\)
24) \(\left(2x^2+x-2013\right)^2+4\left(x^2-5x-2012\right)^2=4\left(2x^2+x-2013\right)\left(x^2-5x-2012\right)\)
25)\(\dfrac{x-4}{x+1}+\dfrac{x-4}{x+1}+\dfrac{8}{3}=\dfrac{x-8}{x+2}+\dfrac{x+8}{x-2}\)
Thanks các cậu vì đã giúp mk
Tìm x biết:
a) \(2x\left(5x-3\right)-\left(2x-1\right)\left(2x+1\right)-8x^2+6x\)
b) \(\left(x^2+2\right)\left(x-1\right)-\left(x-2\right)\left(x^2+2x+4\right)\)
a) \(x-\dfrac{\dfrac{x}{2}-\dfrac{3+x}{4}}{2}=\dfrac{2x-\dfrac{10-7x}{3}}{3}-\left(x-1\right)\)
b) \(x^2-6x-2+\dfrac{14}{x^2-6x+7}=0\)
c) \(\dfrac{8x^2}{3\left(1-4x^2\right)}=\dfrac{2x}{6x-3}-\dfrac{1+8x}{4+8x}\)
d) \(\dfrac{13}{\left(2x+7\right)\left(x-3\right)}+\dfrac{1}{\left(2x+7\right)}=\dfrac{6}{x^2-9}\)
e) \(\left(1-\dfrac{2x-1}{x+1}\right)^3+6\left(1-\dfrac{2x-1}{x+1}\right)^2=\dfrac{12\left(2x-1\right)}{x+1}-20\)