Question 167618
{{{f(x)=x^2}}}
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{{{f(x+h)=(x+h)^2}}}
{{{f(x+h)=x^2+2xh+h^2}}}
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{{{f(x+h)-f(x)=x^2+2xh+h^2-x^2}}}
{{{f(x+h)-f(x)=2xh+h^2}}}
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{{{(f(x+h)-f(x))/h=(2xh+h^2)/h}}}
{{{(f(x+h)-f(x))/h=2x+h}}}