Verified Answer :

meerkat18

(-3i + 4)(3i + 4)

Use the FOIL method

multiply the Firsts: -3i 3i = -9i² = because i² = -1 ⇒ -9i² = -9(-1) = 9
multiply the Outers: -3i 4 = -12i
multiply the Inners: 4 3i = 12i
multiply the lasts: 4 4 = 12

9 - 12i + 12i + 12 = 21

Related Questions