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**s3a** When I try to solve limits I find I always get the answer wrong when dealing with square roots.

Here's an example:

lim x --> - infinity (sqrt(x^2 + x + 1) + x

what I do:

lim x --> - infinity (sqrt(x^2 + x + 1) + x (((sqrt(x^2+x+1) - x)/((sqrt(x^2+x+1) - x))

lim x --> -infinity (x^2 + x + 1 - x^2)/(sqrt(x^2 + x + 1) - x)

lim x --> -infinity (x + 1)/(sqrt(x^2 + x + 1) - x)

lim x --> -infinity (x + 1)/(sqrt(x^2( 1 + 1/x + 1x^2) - x)

lim x --> -infinity (x/x(1 + 1/x)/(sqrt((x^2)/(x^2)( 1 + 1/x + 1x^2) - x/x)