...I have to evaluate the following limits:

a) lim x -> 7

(square root(x+2)) -3 / (x-7

I was unable to solve this

rationalize the numerator ... multiply by

b) lim x -> 0

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

Somehow simplified it to 0 / x+1... this makes no sense.

simplifies to

c) lim x -> -infinity

(square root(4x^2 + 1)) / (3x-5)

first, note that the limit will be less than 0. divide the numerator and denominator by x ...