Browse · MATH Print → jmc algebra intermediate Problem Express (4−5i)(−5+5i) in the form a+bi, where a and b are integers and i2=−1. Solution — click to reveal We simplify, bearing in mind that i2=−1. We get (4−5i)(−5+5i)=4(−5)+4(5i)−5i(−5)−5i(5i)=−20+20i+25i+25=5+45i. Final answer 5 + 45i ← Previous problem Next problem →