if y=x²+x-4, evaluate y given x=2i

Question

if y=x²+x-4, evaluate y given x=2i. this is the first time I have seen this so I am unsure how to proceed.

Answer 1

Let's start by simplifying that squared term:

 

x² = (2i)² = (2i)(2i)=4i²=-4

 

Thus, x²+x-4 becomes (-4)+(2i)-4, which simplifies to -8+2i.

 

Does that help?