Answer:
Cost of tickets: $7. Equation: 40 = 4x + 12.
Step-by-step explanation:
A prime number has exactly two factors, 1 and itself. For example, 13 is a prime number because the only factors of 13 are 1 and 13. The number 8 is not prime because it has four factors: 1, 2, 4 and 8. The number 1 is not a prime number because it only has one factor (itself).
2x-3y=-14/×(-3) <=>-6x +9y=42
3x-2y=-6/×2<=>6x-4y=-12 se reduce -6x cu 6x si ne ramane 5y=30<=>y=6 , luom o ec care o vrem si inlocuim pe y cu 6 ...3x -2x=-6<=>3x-12=-6<=>3x=6<=>x= 2 , x-y=2-6=-4
First task:
To determine this we need to make difference between system that doesn't have solution and system that has infinite number of solution. If when solving equations we get 0 = 0 that means system has infinite number of equations.
If we get 0 = some number that means that system doesn't have solution.
Multiplying first equation of second system by 2 and adding it to second equation we get 0=0 which means that this system has infinite number of solutions.
Answer is second system
Second task:
For this we need to set a system of equations and solve it. System looks like this:
x + y = 224
x*12 + y*8=2520
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x represents older than 18 and "y" 18 and younger than that.
first equation we multiply with -12 and sum it with second.
-4y = -168
y=168/4 = 42
Answer is 42.
