4n-40=7(-2n+2)
4n-40=-14n+14
subtract -4n from both sides
-40 = -18n +14
subtract -14 from both sides
-54=-18n
divide both sides by -18
3 = n
HCF is 6
That should be your answer
Prayers xx
3 (horizontally)
I do not think it is easy to explain this answer.