Answer:
X = 4
Step-by-step explanation:
3x=16-4
3x= 12
X=12/3
X= 4
47 students per room, 45 weren’t in a room
determinant: 
(a) 
D<0 means there are no real roots. there are two complex roots with imaginary components.
(b) D=16+20=36>0
D>0 means there are two real roots
(c) D = 20^2-4*4*25 = 0
D=0 means there is one real root with multiplicity 2
The answer is: 7x + 5 (x + 6) = 138 7x + 5x + 30 = 138 12x = 138 - 30 12x = 108 x = 9 $ = regular pay and overtime = 9 + 6 = 15 $...