need help solving this equation

[Guest]

If a and b are real numbers, i^2=-1 and
(a+b)+5i=9+ai
What is the value for b?

 

[stapel]

Compare the real and imaginary parts:

. . . . .equation: (a + b) + 5i = 9 + ai

. . . . .real: a + b = 9

. . . . .imaginary: 5 = a

Then what is b?

Eliz.

 

[Guest]

thanks alot
I've figured out that the answer is 4.