A. 12*x + 2*y = 90
6*x + 2*y = 60
To write system of equation you just need to sum all solo and ensemble acts and make it equal to how much they will last for.
B. Here we can multiply second equation with negative 1 and add it to first equation.
6x = 30
x = 5
now we replace x in any of 2 equations to get y.
30+2y = 60
2y = 30
y=15
Solo acts are 5 minutes long and ensemble acts are 15 minutes long
Hey Jay,
Since we can't see the graphs, we can't be entirely sure, but given that we are trying to model the population size of a species of bird that is slowly going extinct. I would say the best graph would be a line graph. Line graphs show changes over time so this would be the best graph to use. Hope this helped!
Cheers,
Izzy
If this exact question is repeatedly deleted, it's probably because of the ambiguity of the given equation. I see two likely interpretations, for instance:

or

If the first one is what you intended, then

and it follows that
2<em>k</em> + 8 = 3 ==> 2<em>k</em> = -5 ==> <em>k</em> = -5/2
If you meant the second one, then

which would give
<em>k</em> + 9 = 3 ==> <em>k</em> = -6
And for all I know, you might have meant some other alternative... When you can, you should include a picture of your problem.
55/20 = 2.75
It costs $2.75 per person