(81x-64)-(49x+27)
pretend that there is a +1 in front of the first bracket
pretend that there is a -1 in front of the second bracket
1(81x-64)-1(49x+27)
mutiply the first bracket by 1
(1)(81x)= 81x
(1)(-64)= -64
mutiply the second bracket by -1
(-1)(49x)= -49x
(-1)(27)= -27
81x-64-49x-27
81x-49x-64-27 ( combine like terms)
Answer:
C. 32x-91