Respuesta :

f(x) = 7 - 3x^2

a)
f(9) = 7 - 3(9^2)
f(9) = 7 - 3*81
f(9) = 7 - 243
f(9) = - 236
b)
f(-5) = 7 - 3(-5)^2
f(-5) = 7 - 3*25
f(-5) = 7 - 75
f(-5) =  -68
c)
f(b) = 7 - 3b^2

d)
f(2b) = 7 - 3(2b)^2
f(2b) = 7 - 3(4b^2)
f(2b) = 7 - 12b^2