2.x^2+x/x^2+2x
3. x^2+3x-18/x^2-36
4. 2x^2+11x+5/3x^2+17x+10 1. (20+40x)/(20x) = 20(1+2x)/(20x) = (1+2x)/x
You cannot divide by zero. You will have restrictions when the denominator equals zero.
Set the denominator of the original problem equal to zero.
20x = 0
x = 0 is a restriction.
2. (x^2+x)/(x^2+2x) = x(x+1) / [x(x+2)] = (x+1)/(x+2)
Set the original denominator equal to zero.
x^2+2x = 0
x(x+2) = 0
x = 0 or x+2 = 0
x = 0 and x = -2 are your restrictions.
You should be able to do the other ones.