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:
x = 2.03 cm
Step-by-step explanation:
opposite/hypotenuse = siny
opposite, x = sin(72) * 8
opposite, x = 2.03 cm
Answer: 1 is not in the domain of f g.
Step-by-step explanation:
The ratio of the number of minutes he lifter weights tot the total minutes he worked out is 25: 50. Simplified, the ratio would be 1:2
Answer:
Step-by-step explanation:
6) Let John's sister age be x
John's age = 
{Subtract 7 from both sides}

x = 56
His sister's age = 56 years
7) Longest side is hypotenuse. Use Pythagorean theorem.
hypotenuse² =base² + altituse²
15² = 12² + 9²
225 = 144 + 81
225 = 225
So, Pythagorean theorem is satisfied. So, 15cm , 12 cm ,9 cm will make a right angled triangle.
9) q = -1
7p + 5q -3 = 0
7p + 5*(-1) - 3 = 0
7p -5 - 3 = 0 {Combine like terms}
7p - 8= 0
7p = 8 {Divide both sides by 7}
p = 8/7
10) 8 - 3(x + 1) = 5 {Distributive property: a(b + c) = a*b + a*c}
8 - 3x - 3 = 5 {Combine like terms}
-3x + 5 = 5 {Subtract 5 from both sides}
-3x = 5 - 5
-3x = 0
x = 0
11) -20x⁴ - 7x³ + 5x² + 20 - ( 8x⁴ -7x² + 29x - 17)
= -20x⁴ - 7x³ + 5x² + 20 - 8x⁴ + 7x² - 29x + 17
= -20x⁴ - 8x⁴ - 7x³ + 5x² + 7x² - 29x + 20 + 17
= -28x⁴ -7x³ + 12x² - 29x + 37