Respuesta :

4x^2 + 7x - 5 - (3x^2 - 2x - 4) =
4x^2 + 7x - 5 - 3x^2 + 2x + 4 =
x^2 + 9x - 1 <==
distribute the negative sign through the second parenthesis.  When you do that you'll have..

4x^2+7x-5-3x^2+2x+4

Add like terms and get...

x^2+9x-1