At first find the area of rectangle:
(x + 4)*(x + 1) = x^2 + 5x + 4
Then find the area of triangle:

Then you must do like this
Area of rectangle - Area of triangle = Area of the shaded
x^2+5x+4 - (

)
Integer means number abd the only number there 100
answer
the number of buses is 3
the number of cars is 6
Step-by-step explanation:
total number of the students=165
total number of the vehicles=9
let x represent the number of cars
let y represent the number of buses
x+y=9...........equation 1
(the number of the cars plus the number of the buses= to the number of vehicles )
5x + 45y=165.......equation 2
(the number of student the car can hold plus the number of student the bus can hold= to the total number of the student in a class)
x+y=9.......eqn 1
5x +45y=165....eqn 2
make x the subject of the formula in eqn 1
x+y=9
x= 9-y
substitute for x= 9-y in eqn 2
5(9-y)+45y=165
45-5y+45y=165
-5y+45y=165-45
40y=120
divide both sides by 40
40y÷40=120÷40
y=3
since y represent number of buses,the numbet of bus is 3
Also,substitute for y=3 in eqn 1
eqn 1 is x+y=9
x+3=9
x=9-3
x=6
therefore,the number of cars is 6.