How do you simplify 5i^4 + 3i^2 + 4i^7 - 4? Precalculus Complex Numbers in Trigonometric Form Powers of Complex Numbers 1 Answer Trevor Ryan. Nov 17, 2015 -2-4i Explanation: We may use the fact that i^2=-1 to write the following 5i^4+3i^2+4i^7-4=5(i^2*i^2)+3i^2+4(i^2*i^2*i^2*i)-4 =5-3-4i-4 =-2-4i Answer link Related questions How do I use DeMoivre's theorem to find (1+i)^5? How do I use DeMoivre's theorem to find (1-i)^10? How do I use DeMoivre's theorem to find (2+2i)^6? What is i^2? What is i^3? What is i^4? How do I find the value of a given power of i? How do I find the nth power of a complex number? How do I find the negative power of a complex number? Write the complex number i^17 in standard form? See all questions in Powers of Complex Numbers Impact of this question 1756 views around the world You can reuse this answer Creative Commons License