\(=\dfrac{5+4x+x-3}{7x}\left(x\ne0\right)=\dfrac{5x+2}{7x}\)
\(=\dfrac{5+4x+x-3}{7x}\left(x\ne0\right)=\dfrac{5x+2}{7x}\)
Cho \(A=\dfrac{x^2-5x+6}{x^2+7x+12}.\dfrac{x^3+4x^2}{x^3-x^2}:\dfrac{x^2-4x+4}{x^2+3x}\)
a) Rút gọn A
b) Tìm x để A > 0 ; A < 0 ; A = 0 ; A có nghĩa ; A vô nghĩa
Rút gọn:
\(A=\left(\dfrac{x}{x^2-49}-\dfrac{x-7}{x^2+7x}\right):\dfrac{2x-7}{x^2+7x}+\dfrac{x}{7-x}\)
a)Rút gọn \(A=\dfrac{x^2+2x-3}{x^2+3x-10}:\dfrac{x^2+x-6}{x^2-9x+14}.\dfrac{x^2-4x+3}{x^2+7x+10}\)
b) Tìm x để kết quả rút gọn của A > 0; A < 0; A = 0
Rút gọn \(E=\left[\left(\dfrac{3}{x+1}-\dfrac{x}{x^2+2x+1}\right):\dfrac{2x^2+3x}{x^2+7x}+\dfrac{3}{x+1}\right].\dfrac{x^2+x}{3x+1}\)
Rút gọn:
\(B=\dfrac{x-2}{x+2}\cdot\left(\dfrac{5x+10}{7x-14}+\dfrac{x-2}{3x-6}\right)+\dfrac{3\cdot\left(x^2-4\right)}{2x^2-8x+8}\)
Tính
\(B=\dfrac{1}{x^2+x}+\dfrac{1}{x^2+3x+2}+\dfrac{1}{x^2+5x+6}+\dfrac{1}{x^2+7x+12}+\dfrac{1}{x^2+9x+20}\)
Rút gọn:
\(D=\dfrac{x-2}{x+2}\cdot\left(\dfrac{5x+10}{7x-14}+\dfrac{x-2}{3x-6}\right)+\dfrac{3x^2-12}{2x^2-8x+8}\)
-4x5 ( x3 - 4x2 + 7x - 3 )
Phân tích các đa thức sau thành nhân tử
a, 27x3 - \(\dfrac{1}{27}\)
b, x3+ 4x2 - 29x + 24
c, x2 + 7x + 12
d, 3x2 - 3xy - 5x + 5y