Question

x=(-5.15-5.89i)+(30/(-5.15-5.89i))
i is the square root of (-1)
the answer sholud equal 10.3
x=10.3
but could you show me how , i am having problem to figure it out.
thank you.

Answer 1

since you're adding (not multiplying), you'd have to find the common denominator! when you do this, you multiply both the numerator and denominator with the same number.

(-5.15-5.89i)[(-5.15-5.89i)/(-5.15-5.89i)] + (30/(-5.15-5.89i))

=[(-5.15-5.89i)(-5.15-5.89i)+ 30]/ [-5.15-5.89i]

[(-5.15)(-5.15)+(-5.15)(-5.89i)+(-5.15)(-5.89i)+(-5.89i)(-5.89i)+30]/[-5.15-5.89i]

now simplify. like I said before, every time you see a i^2, replace that with -1!