You are selling tickets for a high school play student tickets cost $4 and adult tickets cost $6, you sell 450 tickets and collect 2340, how many of each type of ticket did you sell

S + A = 450
$4S + $6A = $2340

S + A = 450
-6(S + A = 450)
-6S +-6A = -2700
4S + 6A = 2340

-2S = -360
-2S/-2 = -360/-2
S = 180

S + A = 450
180+ A =450
180-180 + A = 450-180
A = 270

Check
$4S + $6A = $2340
$4(180) + $6(270) = $2340
$720 + $1620 = $2340
$2340 = $2340

Where is the diagram