Respuesta :
[tex]f(x)=4x^2\text{ - 5x + 7}[/tex]
(A) f(x+h)
[tex]\begin{gathered} f(x+h)=4(x+h)^2\text{ - 5(x + h) + 7} \\ =\text{ 4(x + h)(x + h) - 5x - 5h + 7} \\ =4(x^2+2xh+h^2)\text{ - 5x - 5h + 7} \\ =4x^2+8xh+4h^2\text{ - 5x - 5h + 7} \end{gathered}[/tex](B) f(x + h) - f(x)
[tex]\begin{gathered} =4x^2+8xh+4h^2\text{ - 5x - 5h + 7 - }(4x^2\text{ - 5x + 7)} \\ =4x^2+8xh+4h^2-5x-5h+7-4x^2\text{ + 5x - 7} \\ =4x^2-4x^2-5x+5x+7-7+8xh+4h^2\text{ - 5h} \\ \text{ = 0 + 0 + 0 + 8xh + 4h}^2\text{ - 5h} \\ =8xh+4h^2\text{ - 5h} \end{gathered}[/tex](C)
[tex]\begin{gathered} =\text{ }\frac{f(x+h)\text{ - f(h)}}{h} \\ =\text{ }\frac{8xh+4h^2\text{ - 5h}}{h} \\ =\text{ }\frac{8xh}{h}\text{ + }\frac{4h^2}{h}\text{ - }\frac{5h}{h} \\ =\text{ 8x + 4h - 5} \end{gathered}[/tex]