so 2bi4 means 2x4=8xbi=8bi then lets find 4bi9...4x9=36xbi=36bi then youre gonna have 8bi=36bi.
add similar variables. so 44bi=0 so then [(sqaure root)-44](b/c of imaginary number)b=0
then b=0/[(sq.rt.)-44] so then b=0.
so then that means
2(0)[(sq.rt.)-4] = 0
4(0)[(sq.rt.)-9] = 0
so in the end, 2bi4 and 4bi9 is just nothing
and thats the algabreic definition of 2bi4 and 4bi9