If someone is reading my comment so let me tell you here an easy way to calculate the value of i^12 or even i^225 or any other value you just need to devide it with 4 means 12\4 the remainder is 0 and we know that i^0 is 1 and the answer is one and similarly for I ^7 just devide and write your remainder as power of i
Assalamualaikum sir, sir in my proception in 29:16 M.C.Qs no 14 +_4i is not possible because we have to find x that is real number and +_4i is an imaginary number. Thanks