A=number of seats in section A
B=number of seats in section B
C=number of seats in section C
We can suggest this system of equations:
A+B+C=55,000
A=B+C ⇒A-B-C=0
28A+16B+12C=1,158,000
We solve this system of equations by Gauss Method.
1 1 1 55,000
1 -1 -1 0
28 16 12 1,158,000
1 1 1 55,000
0 -2 -2 -55,000 (R₂-R₁)
0 12 16 382,000 (28R₁-R₂)
1 1 1 55,000
0 -2 -2 -55,000
0 0 4 52,000 (6R₂+R₃)
Therefore:
4C=52,000
C=52,000/4
C=13,000
-2B-2(13,000)=-55,000
-2B-26,000=-55,000
-2B=-55,000+26,000
-2B=-29,000
B=-29,000 / -2
B=14,500.
A + 14,500+13,000=55,000
A+27,500=55,000
A=55,000-27,500
A=27,500.
Answer: there are 27,500 seats in section A, 14,500 seats in section B and 13,000 seats in section C.
Answer:
a. S = 3n + 2
b. There while be 62 squares.
Step-by-step explanation:
We know the first term of this sequence is 5. To figure out the equation, subtract the following term from the previous. Do you see a common difference?
8 - 5 = 3
11 - 8 = 3
14 - 11 = 3
We're seeing a constant difference of 3 (which makes this an arithmetic sequence), but the first term is 5. That mean something is being added to make the first term 5. Subtract 3 from 5 to get 2. This means 2 is being added to every multiple of 3, which leads us to the equation: S = 3n + 2.
To find the 20th term of this sequence, substitute n for 20 and do the operations.
S = 3(20) + 2
<em>Multiply 3 by 20, then add 2.</em>
S = 62
The 20th term will have 62 squares.
I got

What we know
cos a=-3/5.
sin b=12/13
Angle A interval are between 180 and 270 or third quadrant
Angle B quadrant is between 90 and 180 or second quadrant.
What we need to find
Cos(b)
Cos(a)
What we are going to apply
Sum and Difference Formulas
Basics Sine and Cosines Identies.
1. Let write out the cos(a-b) formula.

2. Use the interval it gave us.
According to the given, Angle B must between in second quadrant.
Since sin is opposite/hypotenuse and we are given a sin b=12/13. We. are going to set up an equation using the pythagorean theorem.
.




so our adjacent side is 5.
Cosine is adjacent/hypotenuse so our cos b=5/13.
Using the interval it gave us, Angle a must be in the third quadrant. Since cos is adjacent/hypotenuse and we are given cos a=-3/5. We are going to set up an equation using pythagorean theorem,
.




so our opposite side is 4. sin =Opposite/Hypotenuse so our sin a =4/5.Sin is negative in the third quadrant so
sin a =-4/5.
Now use cosine difference formula



Hope this helps
One side is 9.
second side (3x+1) is 28.
third side (4x-9) is 27.
Answer:
I'm not sure if there is enough information here. If you are asking how many books or bookmarks she can buy, you'll need a total amount of money :).