At first I used Greater than or Equal but then I used less than an equal.
Clarification :
The on in RED and BOLD. Why I changed it into less than becase if you noticed we moved the 20 K to the RIGHT side of the inequality and you should know whenever you MOVE the unkown *one with X or K example : 20 K* you CHANGE the Sign 
I hope you got my point
oh ralyy I've never heard about that ''whenever you
MOVE the unkown *one with X or K example : 20 K* you
CHANGE the Sign ''
what I know is that when we just divide or multioly an inquality we change signs only
anyways thanks
but what about the first two questions in my first post Q 3 E [4 a and b] they mentioned real roots but you used less than or equal to get the answer right

by the way I know your method is right ofcourse because you git the right answer but i am just confused sorry of the conflict between the two examples 3E-4a and 3 F-9
Thanks for all your efforts I have made you tired I think