Question: What is the solution?

Solve 6210*r = 12395*r - 6225*r - 3440 for r.

Answer: -86

Question: What is the solution?

Solve 2260 = -75*f + 526 + 9 for f.

Answer: -23

Question: What is the solution?

Solve -450*k + 781*k = 1324 for k.

Answer: 4

Question: What is the solution?

Solve -237*j - 289*j + 450*j + 1064 = 0 for j.

Answer:
14