REPLY QUICK What are the zeros of the quadratic function f(x) = 2x^2 + 8x – 3?

Mathematics · Middle School · Tue Nov 03 2020

Answered on

Given the quadratic function:

f(x) = 2x^2 + 8x - 3

a = 2

b = 8

c = -3

Determine the zeros or the roots of the quadratic function.

Solution:

In order to solve for the roots of an equation, we simply must look at the 2nd and 3rd value. First we must think of two numbers that when added, the answer is 6, and when multiplied, the answer is -3. Hence, if we are unable to find the number, we will use the quadratic formula.

The Quadratic formula:

x = −b ± √(b^2 − 4ac)/2a

is used to solve quadratic equations where a ≠ 0, in the form
ax^2+bx+c=0

When b^2−4ac=0 there is one real root.

When b^2−4ac>0 there are two real roots.

When b^2−4ac<0 there are no real roots, only a complex number.

Substitute the given values to the quadratic formula.


x = −8 ± √(8^2 − 4(2)(-3))/2(2)

x = −8 ± √(64 + 24))/4

x = −8 ± √(88)/4

x = −8 ± 9.38/4

Solve for ±  separately.

x = −8 + 9.38/4

x = 0.345

x = −8 - 9.38/4

 x = -4.345

Final answer:

 x = -4.345

x = 0.345