How do you simplify (-3 + i)(2 + 7i) ? Precalculus Complex Numbers in Trigonometric Form Multiplication of Complex Numbers 1 Answer Lucio Falabella Jan 22, 2016 (-3+i)(2+7i)=-13-19i=-(13+19i) Explanation: Remembering that i^2=-1 You can think that (a+ib) is like a binomial, thus: (-3+i)(2+7i)=(-3times2-3times7i+2timesi+7i^2)= =-6-21i+2i+7times(-1)=(-6-7)+(-21+2)i=-13-19i=-(13+19i) Answer link Related questions How do I multiply complex numbers? How do I multiply complex numbers in polar form? What is the formula for multiplying complex numbers in trigonometric form? How do I use the modulus and argument to square (1+i)? What is the geometric interpretation of multiplying two complex numbers? What is the product of 3+2i and 1+7i? How do I use DeMoivre's theorem to solve z^3-1=0? How do I find the product of two imaginary numbers? How do you simplify (2+4i)(2-4i)? How do you multiply (-2-8i)(6+7i)? See all questions in Multiplication of Complex Numbers Impact of this question 2230 views around the world You can reuse this answer Creative Commons License