Question

Dada a função f(x) = x^2 - 3x determine:
A) f(-3).........B)f(1/4).........C) f(4) - f(-4)/2

Answer 1

$f(-3)=(-3)^2-3*(-3)=9-9=0$

$f(1/4)=(\frac{1}{4} )^2-3\frac{1}{4}=\frac{1^2}{4^2} -\frac{3}{4}$

$=\frac{1}{16} -\frac{3}{4} =\frac{1-12}{16} =\frac{-11}{16}$

$f(4)-=4^2-3*4=16-12=4$

$f(4)-\frac{f(-4)}{2} =4^2-3*4-\frac{(-4)^2-3*(-4)}{2}$

$=16-12-\frac{16+12}{2}=4-\frac{26}{2} =4-13=-9$