Verified Answer :

\(\frac{k}{3-11}\) = - 20

You can subtract the numbers in the parenthesis:
(3-11) = (-8)

Multiply the denominator to both sides so it cancels out and isolates the variable\(\frac{k}{-8}\) × -8 = - 20 × -8
-8 and -8 cancels out

k = 160

Quick check:
\(\frac{160}{(3-11)}\) = -20
\(\frac{160}{-8}\) = - 20
- 20 = - 20
Yes its right

the answer is: k =160