Evaluate the expression and write the result in the form a+bi

Question

Evaluate the expression (-1+2i)-(-8+4i) and write the result in the form a+bi

the real number A equals=

the real number B equals=

 

Answer 1

Hi Dalia;

(-1+2i)-(-8+4i)

Subtracting a negative number is the same as adding a positive number...

-1+2i+8-4i

Combine like terms...

7-2i

a=7

b=-2

Answer 2

( -1 + 2i) - ( -8 + 4i) =

 

 -1 + 2i + 8 - 4i = 7 - 2i