Answer: <em>K = 196</em>
Step-by-step explanation:
We are given the equation
, and we are also given the fact the the 91 is left when the value of x = -5. We have to find the value of k.
1. The first step is to substitute the x for -5.
2. After substituting the x for -5 in all places, ad<em> =91</em> to make it an equation because we know that 91 will remain. After that, simplify the equation.
<em>-4(-5) becomes 20 because multiplying a negative factor by itself or another negative factor makes the product a positive.</em>
<em />
3. Once finished simplifying, add 105 to both sides of the equation in order to get the variable by itself.
1. ![f(x) = x^{3} -4x+k](https://tex.z-dn.net/?f=f%28x%29%20%3D%20x%5E%7B3%7D%20-4x%2Bk)
![-5^{3} -4(-5)+k](https://tex.z-dn.net/?f=-5%5E%7B3%7D%20-4%28-5%29%2Bk)
2.
![-125+20+k=91](https://tex.z-dn.net/?f=-125%2B20%2Bk%3D91)
![-105+k=91](https://tex.z-dn.net/?f=-105%2Bk%3D91)
3. <u>-105</u> + k =<u> 91</u>
+105 +105
![k = 196](https://tex.z-dn.net/?f=k%20%3D%20196)
Hope this helps!