Which is a zero of the quadratic function [tex][tex]$f(x)=16x^2+32x-9?$[/tex][/tex]

A. [tex][tex]$x=-5.25$[/tex][/tex]

B. [tex][tex]$x=-2.25$[/tex][/tex]

C. [tex][tex]$x=-1.25$[/tex][/tex]

D. [tex][tex]$x=-0.25$[/tex][/tex]



Answer :

To solve for the zeros of the quadratic function [tex]\( f(x) = 16x^2 + 32x - 9 \)[/tex], you need to find the values of [tex]\( x \)[/tex] that satisfy the equation [tex]\( f(x) = 0 \)[/tex]. Let's explore which, if any, of the given values of [tex]\( x \)[/tex] satisfy this equation.

1. Checking [tex]\( x = -5.25 \)[/tex]:
[tex]\[ f(-5.25) = 16(-5.25)^2 + 32(-5.25) - 9 \][/tex]
Simplifying inside the parentheses first:
[tex]\[ (-5.25)^2 = 27.5625 \][/tex]
Then,
[tex]\[ f(-5.25) = 16(27.5625) + 32(-5.25) - 9 = 441 - 168 - 9 = 264 \ne 0 \][/tex]
So, [tex]\( x = -5.25 \)[/tex] is not a zero of [tex]\( f(x) \)[/tex].

2. Checking [tex]\( x = -2.25 \)[/tex]:
[tex]\[ f(-2.25) = 16(-2.25)^2 + 32(-2.25) - 9 \][/tex]
Simplifying inside the parentheses first:
[tex]\[ (-2.25)^2 = 5.0625 \][/tex]
Then,
[tex]\[ f(-2.25) = 16(5.0625) + 32(-2.25) - 9 = 81 - 72 - 9 = 0 \][/tex]
So, [tex]\( x = -2.25 \)[/tex] is a zero of [tex]\( f(x) \)[/tex].

3. Checking [tex]\( x = -1.25 \)[/tex]:
[tex]\[ f(-1.25) = 16(-1.25)^2 + 32(-1.25) - 9 \][/tex]
Simplifying inside the parentheses first:
[tex]\[ (-1.25)^2 = 1.5625 \][/tex]
Then,
[tex]\[ f(-1.25) = 16(1.5625) + 32(-1.25) - 9 = 25 - 40 - 9 = -24 \ne 0 \][/tex]
So, [tex]\( x = -1.25 \)[/tex] is not a zero of [tex]\( f(x) \)[/tex].

4. Checking [tex]\( x = -0.25 \)[/tex]:
[tex]\[ f(-0.25) = 16(-0.25)^2 + 32(-0.25) - 9 \][/tex]
Simplifying inside the parentheses first:
[tex]\[ (-0.25)^2 = 0.0625 \][/tex]
Then,
[tex]\[ f(-0.25) = 16(0.0625) + 32(-0.25) - 9 = 1 - 8 - 9 = -16 \ne 0 \][/tex]
So, [tex]\( x = -0.25 \)[/tex] is not a zero of [tex]\( f(x) \)[/tex].

After evaluating each given value, we find that the only solution for [tex]\( f(x) = 16x^2 + 32x - 9 = 0 \)[/tex] from the provided options is:

[tex]\[ \boxed{x = -2.25} \][/tex]