<h2>Steps:</h2>
So firstly, since we know that the coefficient of x² is 1, this means that this is our base equation:
y = x² + bx + c
Now, since we know that the roots are -7 and 1, set y = 0 and set x = -7 and 1 and simplify:
Now with this, we can set up a system of equations to solve for b and c. For this, I will be using the elimination method. For this, subtract the 2 equations:
Now that the c variable has been eliminated we can solve for b. For this, divide both sides by -8 and your first part of your answer is b = 6.
Now that we know the value of b, plug it into either equation to solve for c:
<h2>Answer:</h2>
<u>Putting it together, your final answer is x² + 6x - 7 = 0.</u>
Answer:
3/2
Step-by-step explanation:
Answer: c. z = 1.35; Reject the null hypothesis
Step-by-step explanation:
Let 
be the average life expectancy of its batteries.
As per given , we have
Null hypothesis : 
Alternative hypothesis : 
Since 
is right-tailed and population standard deviation is also known, so we perform right-tailed z-test.
Test statistic : 
where, n= sample size
= sample mean
= Population mean
=population standard deviation
For 
, we have
Critical one-tailed test value for 0.10 significance level :
Decision : Since critical z value (1.28) < test statistic (1.35), so we reject the null hypothesis .
[When critical value is less than the test statistic value , we reject the null hypothesis .]
24* 80/100 = 24*8/10 = 19.2 is the answer.
Step-by-step explanation:
90.......................
