Average (mean) = (sum of all the data) / (# of data)
sum of all the data = (average)(# of data)
Thus for 100 students with an average of 93,
sum of all data = (93)(100) = 9300
and for 300 students with an average of 75,
sum of all data = (75)(300) = 22500
Therefore you would expect the overall average to be
(9300 + 22500) / (100 + 300) = 79.5 %
Now if there are x # of advanced students and y # of regular students, then
x + y = 90 (total # of students) and 93x + 75y = 87(x + y) (overall average)
The second equation can be simplified to x - 2y = 0
Subtracting the two equations yields
x = 60 and y = 90
Therefore you would need 60 advanced and 30 regular students.
-4(4x+3) + (7x -2) = (-16x + -12) + (7x + 2) = -16 + -12 + 7x + 2 = -9x -10
The answer is -9x -10

Let's solve this inequality!

What can we do to solve this inequality? Well, first of all, we can add -7 and 35:

Now, move 20 to the right, using the opposite operation:

Subtract:

Divide both sides by -1 to isolate x:
(Answer)
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<em>Additional comment</em>
When we divide both sides of an inequality by a negative number, we flip the inequality sign.
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I hope you find it helpful.
Feel free to ask if you have any questions.

Cosx=sqrt3/2 and tanx=sqrt3/3
2x+3=7
2x+3-3=7-3
Whenever moving a number to the other side you have to change the sign .
2x= 4
x=2