Answer: A. 85.7
Step-by-step explanation:
Given : Two sections of a class took the same quiz.
Section A had 15 students who had a mean score of 80, and Section B had 20 students who had a mean score of 90.
We know that , 
Then , for section A :


Similarly in Section B, 
Total scores = Sum of scores in sec A+Sum of scores in sec B
=1200+1800=3000
Total students = Students in sec A +Students in sec B
=15+20=35
Now , the mean score for all of the students on the quiz =

Hence, the approximate mean score for all of the students on the quiz = 85.7
Thus , the correct answer is option A. 85.7.
<span>Multiply equation(2) with 4 so that coefficient of become same in both the equations(You can make coefficient of y same and can follow the following procedure.)
</span><span>* Subtract (3) from (1)
* </span>Divide both sides by -19
*Subtract 21 from both sides.
*Divide both sides by 4
so the solution is x= 3 and y= -7
Hope I helped you :)
350 - 213 - 155 + 78 = 60 students not in either
and
so

and you rationalize denominator by multiplying numerator and denominatr by
so that gives--

Your answer is 
Answer: 
<u>Step-by-step explanation:</u>
The formula for factoring a cubic is:
a³ + b³ = (a + b)(a² - ab + b²)
f(x) = x³ + 3³
= (x + 3)(x² - 3x + 9)
To find the zeros, set each factor equal to zero and solve.
0 = x + 3 0 = x² - 3x + 9
-3 = x use quadratic formula

Answer:
