\(\dfrac{x+9}{x+4}-\dfrac{5}{x-4}=\dfrac{-20}{x^2-16}\)ĐKXĐ:x khác +-4
=>\(\dfrac{\left(x+9\right).\left(x-4\right)}{\left(x+4\right)\left(x-4\right)}-\dfrac{5.\left(x+4\right)}{\left(x+4\right).\left(x-4\right)}=\dfrac{-20}{\left(x+4\right).\left(x-4\right)}\)
=> khử mẫu:
=>(x+9).(x-4)-5.(x+4)=-20
=>x2-4x+9x-36-5x-20=-20
=>x2-56=-20
=>x2=62
=>x=6
1/ \(\dfrac{x+4}{4}+\dfrac{3x-7}{5}=\dfrac{7x+2}{20}\)
2/ \(\dfrac{x}{6}+\dfrac{1-3x}{9}=\dfrac{-x+1}{12}\)
3/ \(\dfrac{x-3}{3}-\dfrac{x+2}{12}=\dfrac{2x-1}{4}\)
4/ \(\dfrac{x-2}{4}-\dfrac{2x+3}{3}=\dfrac{x+6}{12}\)
5/ \(\dfrac{2x-1}{12}-\dfrac{3-x}{18}=\dfrac{-1}{36}\)
giải các phương trình sau
1, \(\dfrac{-3}{x-4}-\dfrac{3-5x}{x^2-16}=\dfrac{1}{x+4}\)
2, \(\dfrac{3}{2+x}-\dfrac{x-1}{x^2-4}=\dfrac{2}{x-2}\)
3, \(\dfrac{x-5}{2x-3}-\dfrac{x}{2x+3}=\dfrac{1-6x}{4x^2-9}\)
BT1: Khai triển
\(d,\left(x+2\right)\left(x^2-2x+4\right)\)
\(e,\left(\dfrac{1}{4}-\dfrac{x}{5}\right)\left(\dfrac{x^2}{25}+\dfrac{x}{20}+\dfrac{1}{16}\right)\)
\(A=\dfrac{x-4}{x+5};B=\dfrac{2}{x+4}+\dfrac{x+20}{x^2-16}\)
a.Tính A khi x= -3
b.Rút gọn B
c.Tìm x ϵ Z để P=A.B có giá trị ϵ Z
giải các phương trình sau
1, \(\dfrac{3}{x-3}+\dfrac{4}{x+3}=\dfrac{3x-7}{x^2-9}\)
2, \(\dfrac{3}{x-4}-\dfrac{4}{x+4}=\dfrac{3x-4}{x^2-16}\)
3, \(\dfrac{5x^2-12}{x^2-1}+\dfrac{3}{x-1}=\dfrac{5x}{x+1}\)
thực hiện phép tính
\(\dfrac{x}{x-3}-\dfrac{6}{x}-\dfrac{9}{x^2-3x}\)
\(\dfrac{7}{x}-\dfrac{x}{x+6}+\dfrac{36}{x^2+6x}\)
\(\dfrac{6}{x-3}-\dfrac{2x-16}{x^2-9}-\dfrac{4}{x+3}\)
a.\(\dfrac{4x-5}{x-1}=2+\dfrac{x}{x-1}\) b.\(\dfrac{7}{x+2}=\dfrac{3}{x-5}\) c.\(\dfrac{2x+5}{2x}-\dfrac{x}{x+5}=0\)
d.\(\dfrac{12x+1}{11x-4}+\dfrac{10x-4}{9}=\dfrac{20x+17}{18}\) e.\(\dfrac{11}{x}=\dfrac{9}{x+1}+\dfrac{2}{x-4}\) f.\(\dfrac{14}{3x-12}-\dfrac{2+x}{x-4}=\dfrac{3}{8-2x}-\dfrac{5}{6}\)
m.\(\dfrac{12}{1-9x^2}=\dfrac{1+3x}{1+3x}-\dfrac{1+3x}{1-3x}\) n.\(\dfrac{x+1}{x-1}-\dfrac{x-1}{x+1}=\dfrac{16}{x^2}\) e.\(\left(1-\dfrac{x-1}{x+1}\right)\left(x+2\right)=\dfrac{x+1}{x-1}+\dfrac{x-1}{x+1}\)
a) (2x + 3y)2
b) (x + \(\dfrac{1}{4}\))2
c) (x2 + \(\dfrac{2}{5}\)y) . (x2 - \(\dfrac{2}{5}\)y)
d) (2x + y2)3
e) (3x2 - 2y)2
f) (x + 4) (x2 - 4x + 16)
g) (x2 - \(\dfrac{1}{3}\)) . (x4 + \(\dfrac{1}{3}\)x2 + \(\dfrac{1}{9}\))
giải các phương trình sau
1, \(\dfrac{5x^2-12}{x^2-1}+\dfrac{3}{x-1}=\dfrac{5x}{x+1}\)
2, \(\dfrac{3}{x-5}-\dfrac{15-3x}{x^2-25}=\dfrac{3}{x+5}\)
3, \(\dfrac{-3}{x-4}-\dfrac{3-5x}{x^2-16}=\dfrac{1}{x+4}\)
