Here, I'll help you a little
rewrite the equation as -6k/5 = 12
multiply both sides by 5
-6k=60
divide both sides by -6 to isolate k
k = -10
Hope this helps :)
It would be your first answer because since the MN is a positive you have to subtract it to move it to P and you solved for Q

Sorry that's all i know
<h3>that is in my answer</h3>
<h2>#carryonlearning:-D</h2>
Number of strings =

= 21 x 21 x 21 x 21 x 21 x 5 = 20 420 505
Answer: 20 420 505