The solution to the quadratic equation are option C) x= -5 and option E) x=3.
<u>Step-by-step explanation</u>:
The given quadratic equation is x²+2x-15 = 0.
Using the factorization method,
- product of the roots should be -15.
- Sum of the roots should be 2.
⇒ -15 = 5 
-3
⇒ 2 = 5+(-3)
(x+5)(x-3) = 0
Therefore, x = -5 and x = 3
Answer:
You <u>solve</u> the equation.
Step-by-step explanation:
The process of finding variable values that make the equation true is called <em>solving</em> the equation.
Answer:
Solution : 
Step-by-step explanation:
![-3\left[\cos \left(\frac{-\pi }{4}\right)+i\sin \left(\frac{-\pi \:}{4}\right)\right]\:\div \:2\sqrt{2}\left[\cos \left(\frac{-\pi \:\:}{2}\right)+i\sin \left(\frac{-\pi \:\:\:}{2}\right)\right]](https://tex.z-dn.net/?f=-3%5Cleft%5B%5Ccos%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%7D%7B4%7D%5Cright%29%2Bi%5Csin%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%5C%3A%7D%7B4%7D%5Cright%29%5Cright%5D%5C%3A%5Cdiv%20%5C%3A2%5Csqrt%7B2%7D%5Cleft%5B%5Ccos%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%5C%3A%5C%3A%7D%7B2%7D%5Cright%29%2Bi%5Csin%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%5C%3A%5C%3A%5C%3A%7D%7B2%7D%5Cright%29%5Cright%5D)
Let's apply trivial identities here. We know that cos(-π / 4) = √2 / 2, sin(-π / 4) = - √2 / 2, cos(-π / 2) = 0, sin(-π / 2) = - 1. Let's substitute those values,
=
÷ 
= 
÷ 
= 
÷ 
= 
÷ 
=
As you can see your solution is the last option.
Answer:
f(t) = 5×0.87^t
Step-by-step explanation:
The general form for an exponential function described in this fashion is ...
... f(t) = (starting value) × (1 + (percent change))^t
Here, the "percent change" is -13%, or -0.13.
Then the value (1 + percent change) is (1 + (-0.13)) = 0.87. Putting this and the starting value into the form above, we have ...
... f(t) = 5 × 0.87^t
