4/5-5i? can someone solve this for me?

Question

it is a math question and i cant get the answer right for anything.

4 / 5-5i

and

4x^2+25=20x

I have tried to solve them but cant seem to get the right answer thanks.

Answer 1

Favorite Answer

Do you mean 4/(5-5i) or 4/5 - 5i? Because the two are different. For the first case, multiply it by (5+5i)/(5+5i)

Answer 2

4 / 5-5i = 4/5 - 4/5i = 4/5(1-1i)

(nothing much to do here)

4x^2+25=20x

4x^2 - 20x + 25 = 0

4(x^2 - 5x) = -25

x^2 - 5x = -25/4

x^2 - 5x + 25/4 = -25/4 + 25/4 =0

(x - 5/2)^2 = 0

x - 5/2 = 0

x = 5/2

Answer 3

I'm not sure. Sorry...