help with a basic differentiability and derivative function

very basic problem...can anyone help me with the proof?

f(x) = x^2-3x+8 if x>1
f(x) = 2x^2+x+3 if x=<1

using epsilon-delta property can you prove that f(x) is differentiable
at all points except x=1
and that it is not differentiable at 1?

thanx

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