Here are some solutions: (there are actually an infinite amount of them)
x = 0 , y = 7
x = 1 , y = 8
x = 2 , y = 9
x = 3 , y = 10
x = 4 , y = 11
x = 42 , y = 49
x = pi , y = pi + 7
Base = Height, Let them be x.

Solve quadratic equation:
x=6, x=-2(rejected because base and height is positive)
6x6/2 =18
Answer:
-21.5
Step-by-step explanation:
-12-6=-18 minus 3.5=-21.5