How do you divide x^2/(2x + 4)?

1 Answer
Apr 21, 2017

There are several methods. I will try to show you long division.

Explanation:

Write the dividend with 0s for the missing terms:

color(white)( (2x+4)/color(black)(2x+4))color(white)((x^2+0x+0))/(")" color(white)(x)x^2+0x + 0)

Please observe that x^2/(2x) = 1/2x, therefore, we put 1/2x in the quotient:

color(white)( (2x+4)/color(black)(2x+4))(1/2xcolor(white)(0x+0))/(")" color(white)(x)x^2+0x + 0)

We multiply 1/2x(2x+4) = x^2+2x and then we subtract this underneath:

color(white)( (2x+4)/color(black)(2x+4))(1/2xcolor(white)(0x+0))/(")" color(white)(x)x^2+0x + 0)
color(white)(".............")ul(-x^2-2x)
color(white)(".....................")-2x

Please observe that (-2x)/(2x) = -1, therefore, we add -1 in the quotient:

color(white)( (2x+4)/color(black)(2x+4))(1/2x-1color(white)(+0))/(")" color(white)(x)x^2+0x + 0)
color(white)(".............")ul(-x^2-2x)
color(white)(".....................")-2x

We multiply -1(2x+4) = -2x-4 and then we subtract this underneath:

color(white)( (2x+4)/color(black)(2x+4))(1/2x-1color(white)(+0))/(")" color(white)(x)x^2+0x + 0)
color(white)(".............")ul(-x^2-2x)
color(white)(".....................")-2x+0
color(white)("........................")ul(2x+4)
color(white)("................................")4" " larr This is the remainder.

You can write the remainder as 4/(2x+4) or 2/(x+2)

The results of the division is:

x^2/(2x + 4)= 1/2x-1+2/(x+2