Answer:
see explanation
Step-by-step explanation:
(a)
To evaluate f(- 2) substitute x = - 2 into f(x) , that is
f(- 2) = 9 - 4(- 2)² = 9 - 4(4) = 9 - 16 = - 7
(b)
Similarly substitute x = - 3 and x = 3 into f(x)
f(- 3) = 9 - 4(- 3)² = 9 - 4(9) = 9 - 36 = - 27
f(3) = 9 - 4(3)² = 9 - 4(9) = 9 - 36 = - 27
(c)
let f(x) = 0 , then
9 - 4x² = 0 ( add 4x² to both sides )
9 = 4x² ( divide both sides by 4 )
[tex]\frac{9}{4}[/tex] = x² ( take the square root of both sides )
± [tex]\sqrt{\frac{9}{4} }[/tex] = x
± [tex]\frac{\sqrt{9} }{\sqrt{4} }[/tex] = x
± [tex]\frac{3}{2}[/tex] = x
That is x = - [tex]\frac{3}{2}[/tex] or x = [tex]\frac{3}{2}[/tex]
