7/(4q + 1) = 14/(7 - 2q)
Divide by 7
1/(4q + 1) = 2/(7 - 2q)
Invert
4q + 1 = (7 -2q)/2
Multiply by 2
8q + 2 = 7 - 2q
Add to 2q to each side
10q + 2 = 7
Subtract 2 from each side
10q = 5 and q = 1/2
You could have simply done a cross multiplication, but then the collection process would have been messier, not harder but messier.