Answer: k = 63
Step-by-step explanation: You need to multiply the left side by its reciprocal to move the numbers to the right. You also need to multiply by k on the right side to get it alone on the left. This will result in
(9/3)(3/9) = (21/k)(9/3) simplified
1 = 189/3k • k then multiply by k
k = 189/3 simplify
k = 63
