How do you simplify #(-2+i)(-5+8i)#?

1 Answer
Aug 30, 2016

#2-21i#

Explanation:

Simplify by #color(blue)"distributing brackets and collecting like terms"#

#rArr(-2+i)(-5+8i)=10-5i-16i+8i^2#

#color(orange)"Reminder " color(red)(|bar(ul(color(white)(a/a)color(black)(i^2=(sqrt(-1))^2=-1)color(white)(a/a)|)))#

#rArr10-5i-16i+8i^2=10-21i-8=2-21i#

#rArr(-2+i)(-5+8i)=2-21i#