If 5^5 × 5^7 = (5^4)^x , then what is the value of x?	Choose the correct choice from the following choices:
A) 2
B) 3
C) 4
D) 5
E) 6

Rationale: 5 ^ 5 × 5 ^ 7 = ( 5 ^ 4 ) ^ x 5 ^ ( 5 + 7 ) = 5 ^ ( 12 ) with multiplying numbers with exponents it ' s the same as adding the exponents 5 ^ 12 = ( 5 ^ 4 ) ^ x since base is same , we can equate powers : when raising an exponent to an exponent , it ' s the same as multiplying them , therefore : 12 = 4 x x = 3 ans . b ) 3
Answer: B