Remember i^2 = -1 so (4i)^2 = -16
Multiply the first fraction by (3 - 4i)/(3 - 4i) and the second fraction by (3 + 4i)/(3 + 4i)
= (3 - 4i)(3 - 4i)/(3 + 4i)(3 - 4i) + (3 + 4i)(3 + 4i)/(3 - 4i)(3 + 4i)
= (9 - 8i - 16)/(9 - -16) + (9 + 8i - 16)/(9 - -16)
= (-7 - 8i)/25 + (-7 + 8i)/25
= (-7 - 8i -7 + 8i)/25
= -14/25 which is the first option shown