Question

f(x)= -x²+4x+5; Calcule:

a)f (4)=
b)f(3)=
c)f(2)=
d)(1)=
e) Construa o grafico

Answer 1

y = -x² + 4x + 5

a) F(4)

F(4) = -(4)² + 4.(4) + 5
F(4) = -16 + 16 + 5
F(4) = 5

b) F(3) 

F(3) = -(3)² + 4.(3) + 5
F(3) = -9 + 12 + 5
F(3) = 3 + 5
F(3) = 8

c) F(2)

F(2) = -(2)² + 4.(2) + 5
F(2) = -4 + 8 + 5
F(2) = 4 + 5
F(2) = 9

d) F(1)

F(1) = -(1)² + 4.(1) + 5
F(1) = -1 + 4 + 5
F(1) = 3 + 5
F(1) = 8