Thread: a+bi=0 only when a=0 and b=0 right?

1. a+bi=0 only when a=0 and b=0 right?

a+bi=0 only when a=0 and b=0 right?

I was doing an SAT math level 1 problem that started with:

y=7-x+(x+2)i

so I changed it to:

0 = 7-x-y + (x+2)i

So b=0 --> x=-2 --> y=9 , right?

2. Re: a+bi=0 only when a=0 and b=0 right?

Originally Posted by lamp23
a+bi=0 only when a=0 and b=0 right?
Yes.

Originally Posted by lamp23
I was doing an SAT math level 1 problem that started with:

y=7-x+(x+2)i

so I changed it to:

0 = 7-x-y + (x+2)i

So b=0 --> x=-2 --> y=9 , right?
Yes. The real and imaginary parts must be equal so you solve the equations $x+2=0 \text{ and } 7-x-y=0$ which is what you did in your head