How do you add or subtract (x+6)/(5x+10) - (x-2)/(4x+8)?

1 Answer
May 25, 2015

Notice that the denominator of each of these terms is a simple multiple of (x+2), so we only need to multiply by constants to make the denominators of the two terms the same:

(x+6)/(5x+10)-(x-2)/(4x+8)

=(x+6)/(5(x+2))-(x-2)/(4(x+2))

=(4*(x+6))/(4*5(x+2))-(5*(x-2))/(5*4(x+2))

=(4(x+6))/(20(x+2))-(5(x-2))/(20(x+2))

=(4(x+6)-5(x-2))/(20(x+2))

=(4x+24-5x+10)/(20(x+2))

=(14-x)/(20(x+2))

=(14-x)/(20x+40)