Okay so where's the math question(s)?
Answer:
They used 6 vans and 3 buses
Step-by-step explanation:
x + y= 9
13x + 40y= 198
x= 9 - y
13(9 - y) + 40y= 198
117 - 13y + 40y= 198
27y= 81
y= 3
9-3= 6
Answer:
5x - y = 27
Step-by-step explanation:
Slope is the direction of line and it is calculated as,

where (x₁, y₁) is any two points on the line.
Here, we have given that
Slope = 5 and (x₁, y₁) = (5, -2)
∴ 
⇒ 5(x - 5) = y + 2
⇒ 5x - 25 = y + 2
⇒ 5x - y = 27
Hence, the equation of a line is: 5x - y = 27