Respuesta :
Answer:
Β day 0, day 120
Step-by-step explanation:
You want to find the value of x that makes both y-values be the same:
Β y = y
Β 30x +10 = -x^2 +150x +10
Β x^2-120x = 0 . . . . subtract the right side of the equation
Β x(x -120) = 0 . . . . . factor
Values of x that make this true are x=0 and x=120.
The same number of each car was sold on day 0 and day 120.

Both equations should be equal
- 30x+10=-xΒ²+150x+10
- 30x=-xΒ²+150x
- -120x=-xΒ²
- xΒ²=120x
- x=120 or 0
So the days are 0 and 120