Answer:
C
Step-by-step explanation:
think in general
(y + c)² = y² + 2cy + c²
only A and C have a square number as constant term (36 and 81).
and while it is possible to have any real number as c, but the 2cy part needs to fit to the c² part.
6y = 2cy
2c = 6
c = 3
but 3² is 9 and not 36. so, no fit.
25y = 2cy
2c = 25
c = 12.5
but 12.5² is 156.25 and not 200. so, no fit.
18y = 2cy
2c = 18
c = 9
and 9² is indeed 81. so, this fits.
36y = 2cy
2c = 36
c = 18
but 18² is 324 and not 60. so, no fit.
so, only C is a correct answer.
