#1.
4 + 2y = 9 + 2y (2y cancelled out...4 can't equal 9
Answer: no solution
#2.
Total paid : $27.90 + $5 = $32.90
2 movie tickets = $20 (each costs $10)
2 popcorns = $11.00 (each cost $5.50)
$20 + $11 = $31
So $32.90 - $31 = $1.90
So soft drink costs $1.90
#3.
u + 2 = 4 solve for u
subtract 2 to both sides
u + 2 - 2 = 4 - 2
simplify
u = 2