Question

f(-1) e f(1/2) sendo f(x)= -x²+2x

Answer 1

se f(-1) , então x = -1
f(x) = -x ² +2x
f(x) = -(-1)² + 2 . (-1)
f(x) = -(-1).(-1) + 2 .(-1)
f(x) = -1 - 2
f(x) = -3


quando f(1\2), x=1\2
f(x) = -x² + 2x
f(x) = -(1\2)² + 2.1\2
f(x) = -(1\2).(1\2) + 2.1\2
f(x) = -1\4 + 2\2
f(x) = - 1 + 4 \ 4
f(x) = 3\4 = 0,75           

Answer 2

$f(-1)=-(-1)^2+2(-1)\\f(-1)=-(1)+(-2)\\f(-1)=-3\\\\\\f(\frac{1}{2})=-(\frac{1}{2})^2+2*\frac{1}{2}\\f(\frac{1}{2})=-(\frac{1}{4})+\frac{2}{2}=>\frac{-1+4}{4}\\\\f(\frac{1}{2})=\frac{3}{4}$