Need help

(25 + ki)(3 + 2i)  =  75 + 50i + 3ki + 2ki²   =   75 + 50i + 3ki - 2k

Let's find what value of  k  makes  50i + 3ki  =  0

50i + 3ki  =  0

i(50 + 3k)  =  0

50 + 3k  =  0

3k  =  -50

k  =  -$\frac{50}{3}$

When  k  =  -$\frac{50}{3}$  ,    (25 + ki)(3 + 2i)   is a real number.

Thanks :)