-5x-4x^2+9
a.-4
b.-5
c.5
d.9
I keep doing it but my answers don't match :(
To find the value of x in the expression -5x - 4x^2 + 9, you need to solve the equation for x. Let's break down the steps:
Given expression: -5x - 4x^2 + 9
To solve the equation, set it equal to zero:
-5x - 4x^2 + 9 = 0
Rearrange the terms in descending order:
-4x^2 - 5x + 9 = 0
This equation is a quadratic equation in the form ax^2 + bx + c = 0, where a = -4, b = -5, and c = 9.
Now, you can solve the quadratic equation using methods such as factoring, completing the square, or using the quadratic formula.
Since the options provided are numerical values rather than solutions to the equation, you need to find the value of x that makes the equation equal to zero.
One way to solve this equation is by factoring. However, in this case, factoring may not be straightforward. So, let's use the quadratic formula:
The quadratic formula is given by x = (-b ± √(b^2 - 4ac)) / (2a).
Plugging in the values from the equation -4x^2 - 5x + 9 = 0, we get:
x = (-(-5) ± √((-5)^2 - 4(-4)(9))) / (2(-4))
Simplifying further:
x = (5 ± √(25 + 144)) / (-8)
x = (5 ± √169) / (-8)
x = (5 ± 13) / (-8)
This gives us two potential solutions:
x = (5 + 13) / (-8) = 18 / (-8) = -9/4
x = (5 - 13) / (-8) = -8 / (-8) = 1
Now, let's compare these solutions with the options given: a, b, c, d.
a. -4: Neither of the solutions matches.
b. -5: Neither of the solutions matches.
c. 5: Neither of the solutions matches.
d. 9: Neither of the solutions matches.
None of the provided options match the solutions obtained from solving the equation. It appears that the options given may not correspond to the value of x in the original expression. Double-check the question or consult with your instructor to ensure the correctness of the given options.