( c^2 )^3 = 64 <=>( c^2 )^3 = 4^3 <=> c^2 = 4 <=> c = 2 or c = -2.
Let x be the month on which the fee for two plans are equal.
Therefore,
150 + 10x = 50 + 30x
10x - 30x = 50 - 150
-20x = -100
x = 5
Cumulative cost = 150 + 10(5)
= 150 + 50
= 200
Hence, Karan will pay a cumulative cost of $200 dollars with either plan to go to the gym for 5 months.
X = -17/8
Do you need explanation?