ta co dang tong quat cho tu so la : n^4+4=(n^2+2)^2=(n^2+2n+2)(n^2-2n+2)=[(n-1)^2+1][(n+1)^2+1]
Nen A=(0+1)(2^2+1)/(2^2+1)(4^2+1) . (4^2+1)(6^2+1)/(6^2+1)(8^2+1) .........(20^2+1)(22^2+1)/(22^2+1)(24^2+1) = 1/24^2+1=1/577
Tính (rút gọn):
\(\frac{2}{\left(x-3\right).\left(x-1\right)}+\frac{-7}{\left(x+4\right).\left(x-3\right)}+\frac{4}{x.\left(x+4\right)}\)
giúp mk với tứ tư mk phải nộp rùi
bài 1:
a, \(2x\left(3x^2-5x+3\right)\)
b, \(-2x\left(x^2+5x-3\right)\)
c, \(\dfrac{-1}{2}x\left(2x^3-4x+3\right)\)
bài 2:
a,\(\left(2x-1\right).\left(x^2-5-4\right)\)
b,\(-\left(5x-4\right).\left(2x+3\right)\)
c,\(\left(2x-y\right).\left(4x^2-2xy+y^2\right)\)
d,\(\left(3x-4\right).\left(x+4\right).\left(5-x\right).\left(2x^2+3x-1\right)\)
e,\(7\left(x-4\right)-\left(7x+3\right).\left(2x^2-x+4\right)\)
bài 3:
c/m rằng gtri của biểu thức ko phụ thuộc vào gtri của biến
a,\(x\left(3x+12\right)-\left(7x-20\right)+x^2\left(2x-3\right)-x\left(2x^2+5\right)\)
b,\(3\left(2x-1\right)-5\left(x-3\right)+6\left(3x-4\right)-19x\)
bài 4 :tìm x biết
a, \(3x+2\left(5-x\right)=0\)
b,\(x\left(2x-1\right).\left(x+5\right)-\left(2x^2+1\right).\left(x+4,5\right)=3,5\)
c,\(3x^2-3x\left(x-2\right)=36\)
d,\(\left(3x^2-x+1\right).\left(x-1\right)+x^2.\left(4-3x\right)=\dfrac{5}{2}\)
Giải các phương trình
a)\(\dfrac{15}{4}-2,5:\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=3\)
b) \(6,5-\dfrac{9}{4}:\left|x+\dfrac{1}{3}\right|=2\)
c) \(\left|\dfrac{5}{4}x-\dfrac{7}{2}\right|-\left|\dfrac{5}{8}x+\dfrac{3}{5}\right|=0\)
Giair phương trình
\(8\left(x+\dfrac{1}{x}\right)+4\left(x^2+\dfrac{1}{x^2}\right)^2=\left(x+4\right)^2+4\left(x+\dfrac{1}{x}\right)^2\left(x^2+\dfrac{1}{x^2}\right).\)
giúp mik vs mn ơi
giải phương trình
1)\(\left(x-2\right)\left(3+2x\right)-2x\left(x+5\right)=6\)
2)\(x^2-4-\left(x-5\right)\left(x-2\right)=0\)
3)\(\dfrac{x-3}{3}-\dfrac{x+2}{2}=\dfrac{x}{6}\)
4)\(\dfrac{x+2}{x-2}-\dfrac{x-2}{x+2}+\dfrac{3x-1}{x-4}-6\)
5)\(\dfrac{96}{x^2-16}=\dfrac{2x-1}{x+4}+\dfrac{3x-1}{x-4}-6\)
cho biểu thức
\(P=\left[\dfrac{x^2-2x+4}{x-2}\div\left(x^3+8\right)+\dfrac{x-2}{x^3+8}\cdot\dfrac{x^2-2x+4}{x^2-4}\right]\cdot\left(x^2-4\right)\)
a, rút gọn P
b, tính P biết \(x=-\dfrac{1}{2}\)
\(\dfrac{2-\left(ab+bc+ca\right)}{\left(a-\dfrac{4}{3}\right)^2+\left(b-\dfrac{4}{3}\right)^2+\left(c+\dfrac{4}{3}\right)^2}\)Cho a+b+c=2.Tính gtbt:
rút gọn các phân thức
a,\(\dfrac{7xy^3\left(x-2y\right)}{14x^2y^2\left(x-2y\right)^2}\)
b,\(\dfrac{4a^2-8ab}{2\left(2b-a\right)^3}\)
c,\(\dfrac{3x^3-3x}{x^4-1}\)
d,\(\dfrac{45x\left(3-x\right)}{15x\left(x-3\right)^3}\)
Giúp mk với các bạn. Trình bày chi tiết giúp mk nhá !
a) \(\left(\dfrac{1}{4}x-1\right)+\left(\dfrac{2}{3}x-2\right)-\left(\dfrac{5}{8}x+1\right)=5\)
b) \(2x-10-\text{[}3x-13-\left(3-5x\right)-4\text{]}=7\)
c)\(\left(\left|2x-1\right|-3\right).\left(-2\right)+\left(-5\right)=6\)
