Hey 1200 seat theater sells two types of tickets for a concert. premium seats sell for $30 each and regular seats so for $20 each at one event $30,180 was collected and ticket sales with 10 seats left on so how many for each type of ticket was sold

X = premium seats
y = regular seats
You need two equations: (x + y - 10 = 1200) and (30x + 20y = 30,180)
1.) Isolate one variable
y = 1,210 - x
2.) Plug the new equation into the second ORIGINAL equation
30x +20(1,210 - x) = 30,180
3.) Ditribute
30x + 24,200 - 20x = 30,180
4.) Add like terms
10x + 24,200 = 30,180
5.) Subtract 24,000 from either side
10x = 6,180
6.) Solve for x
x = 618
7.) Plug in x to the equation of your choosing
618 + y - 10 = 1200
8.) Solve for y
608 + y = 1,200
y = 592
The theater sold 592 regular seats and 618 premium seats.