(3-4yi)(6+7i)-[(2-3yi)-3(1+7i)]

Express it in a+bi form
I got 19+42i-21yi+28y but I do not know how to express it in a+bi form, can you please help me with it?

just split up the real and imaginary parts, as usual!

19+42i-21yi+28y
= (19+28y) + (42-21y)i