IDNLearn.com is your reliable source for expert answers and community insights. Our platform provides trustworthy answers to help you make informed decisions quickly and easily.

What are the zeros of the quadratic function [tex]\( f(x) = 2x^2 + 16x - 9 \)[/tex]?

A. [tex]\( x = -4 - \sqrt{\frac{7}{2}} \)[/tex] and [tex]\( x = -4 + \sqrt{\frac{7}{2}} \)[/tex]

B. [tex]\( x = -4 - \sqrt{\frac{25}{2}} \)[/tex] and [tex]\( x = -4 + \sqrt{\frac{25}{2}} \)[/tex]

C. [tex]\( x = -4 - \sqrt{\frac{21}{2}} \)[/tex] and [tex]\( x = -4 + \sqrt{\frac{21}{2}} \)[/tex]

D. [tex]\( x = -4 - \sqrt{\frac{41}{2}} \)[/tex] and [tex]\( x = -4 + \sqrt{\frac{41}{2}} \)[/tex]


Sagot :

To determine the zeros of the quadratic function [tex]\( f(x) = 2x^2 + 16x - 9 \)[/tex], we use the quadratic formula. The quadratic formula states:

[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

where [tex]\( a \)[/tex], [tex]\( b \)[/tex], and [tex]\( c \)[/tex] are the coefficients of the quadratic equation [tex]\( ax^2 + bx + c = 0 \)[/tex].

In our case, the coefficients are:
[tex]\[ a = 2, \quad b = 16, \quad c = -9 \][/tex]

First, let's compute the discriminant, [tex]\( \Delta \)[/tex]:
[tex]\[ \Delta = b^2 - 4ac \][/tex]
[tex]\[ \Delta = 16^2 - 4 \cdot 2 \cdot (-9) \][/tex]
[tex]\[ \Delta = 256 + 72 \][/tex]
[tex]\[ \Delta = 328 \][/tex]

Now, we use the quadratic formula to find the roots:
[tex]\[ x = \frac{-b \pm \sqrt{\Delta}}{2a} \][/tex]
[tex]\[ x = \frac{-16 \pm \sqrt{328}}{2 \cdot 2} \][/tex]
[tex]\[ x = \frac{-16 \pm \sqrt{328}}{4} \][/tex]

Next, we simplify [tex]\( \sqrt{328} \)[/tex]:
[tex]\[ \sqrt{328} = \sqrt{4 \cdot 82} = 2\sqrt{82} \][/tex]

Substituting this back into the formula, we get:
[tex]\[ x = \frac{-16 \pm 2\sqrt{82}}{4} \][/tex]
[tex]\[ x = \frac{-16}{4} \pm \frac{2\sqrt{82}}{4} \][/tex]
[tex]\[ x = -4 \pm \frac{\sqrt{82}}{2} \][/tex]

To match our solutions with the given options, we convert [tex]\( \sqrt{82} \)[/tex] in another form:
[tex]\[ \frac{\sqrt{82}}{2} = \sqrt{\frac{82}{4}} = \sqrt{\frac{41}{2}} \][/tex]

Thus, the zeros of the quadratic function are:
[tex]\[ x = -4 - \sqrt{\frac{41}{2}} \][/tex]
[tex]\[ x = -4 + \sqrt{\frac{41}{2}} \][/tex]

Hence, the correct option is:
[tex]\[ x = -4 - \sqrt{\frac{41}{2}} \quad \text{and} \quad x = -4 + \sqrt{\frac{41}{2}} \][/tex]