B. 1/4
Explanation:
1/2 = .5
.5 x .5 = 1/4
-3
144
-7
49/4 or 12.25
369 must be added to get 518
9
Adding 100 completes the square. { I wonder why you want to complete the square when the expression already factors as x(x-20) }.
Decomposers must be added to any food chain or food web to form a complete food cycle.
26
9
1
-17