Question

rút gọn
a) x^7 - 2x^3 / 2x^4 - x^3
b) (x+2)^2 - (x-2)^2 / 16x
c) 24,5x^2 - 0,5y^2 / 3,5x^2 - 0,5xy

Answer 1

\(a,\dfrac{x^7-2x^3}{2x^4-x^3}=\dfrac{x^3\left(x^4-2\right)}{x^3\left(2x-1\right)}=\dfrac{x^4-2}{2x-1}\)

\(b,\dfrac{\left(x+2\right)^2-\left(x-2\right)^2}{16x}=\dfrac{\left(x+2-x+2\right)\left(x+2+x-2\right)}{16x}=\dfrac{4.2x}{16x}=\dfrac{1}{2}\)

\(c,\dfrac{24,5x^2-0,5y^2}{3,5x^2-0,5y^2}=\dfrac{0,5\left(49x^2-y^2\right)}{0,5\left(7x^2-y^2\right)}=\dfrac{49x^2-y^2}{7x^2-y^2}\)

Answer 2

a) \(\dfrac{x^7-2x^3}{2x^4-x^3}=\dfrac{x^3\left(x^4-2\right)}{x^3\left(2x-1\right)}=\dfrac{x^4-2}{2x-1}\)

b)\(\dfrac{\left(x+2\right)^2-\left(x-2\right)^2}{16x}=\dfrac{x^2+4x+4-\left(x^2-4x+4\right)}{16x}\)=\(\dfrac{x^2+4x+4-x^2+4x-4}{16x}=\dfrac{8x}{16x}=\dfrac{1}{2}\)