the expression is g(x)= 4x^2+3
g(x+h) = 4(x+h)^2+3
substitute the values in the given formula.
[tex]\frac{4(x+h)^2+3-(4x^2+3)}{h}[/tex]solve the expression.
[tex]\frac{4(x^2+2xh+h^2)+3-4x^2-3}{h}=\frac{4x^2+8xh+4h^2+3-4x^2-3}{h}[/tex]The term 4h^2 is too small. so we can neglect it.
[tex]\frac{8xh}{h}=8x[/tex]So the answer is 8x.