f(x) = 3x^2 - 2x + 4



f(-2)= 3(-2^2)-2(-2)+4    <--- that step is just fine.

  +2             +2       <--- that step is totally wrong

   0              0       <--- that step is totally wrong   

     3*2^2 /-2+4=         <--- that step is totally wrong

             

        f= -2             <--- that step is totally wrong



Let's go back to where you went astray:



f(x) = 3x^2 - 2x + 4



f(-2)= 3(-2^2)-2(-2)+4



You leave the left side of the equal sign just as it is, f(-2)



But the right side you must simplify using the PEMDAS order of

operations..  



You take this:



f(-2) = 3(-2^2)-2(-2)+4



Do the exponent:



f(-2) = 3(-4)-2(-2)+4



Do the multiplications and divisions (there are no divisions)



f(-2) = -12+4+4



f(-2) = -4



You leave the left side as it is.  It does not mean f times x.



f(-2) = -4



is read "f of negative two equals negative four".



Edwin 

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