the first one just calcutae the whole rectangle then minus out the 2 triangles.
area = 7x3 - 3x2 ( don't need to divide it by 2 again because anyway there's 2 of it)
= 21- 6
= 15
the second one is just divide in 2 section, one is the square, and the other is the triangle.
area= 9x9 + 6x13/2
= 81 + 39
= 120
