Science is the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.
Answer: 81
To get this answer, you do two things
1) Take half of the x coefficient 18 to get 9
2) Square the result from the previous step to get 9^2 = 9*9 = 81
This value is added on to get x^2+18x+81 which factors to (x+9)^2 confirming we have a perfect square trinomial
Answer:

Step-by-step explanation:
First you need to break the shape up to rectangles to make it easier to solve.
bottom rectangle : 15 x 3 = 45m^2
Top rectangle : 12 x 3=36m^2
Middle rectangle : 12-3-3=6 (because we already solved the top and bottom part of it)
we need to work out the base so we do 15-5= 5cm
6 x 5 = 30m^2
add them all together
30+36+45=111m^2