Right answer gets brainliest

Answer:
(i) therefore b is greater. (ii) a) a = 5 b) b = 15
Step-by-step explanation:
(i)
when a = -3, then c is -20 and b is [ 4(-3)-5 ] = -17 .
therefore b is greater.
(ii) when c is 21,
a = 5
b = 4a - 5
b = 4(5)-5
b = 15