Answer:
2
Step-by-step explanation:
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.
Answer:
a=-108
Step-by-step explanation:
a+22=-86 both sides -22
a+22-22=-86-22
a=-108
