I believe the 3rd answer down if the information you provided is correct
Squaring the sum on the top, rules out 1 and 2 (not squaring the 7 only)
then 4 times the difference. so I believe 4 (x-1) on the bottom.
It is 3.9 I hope this will help you
10(-1c+7)-3c
(-10c+70)-3c
-13c+70 is your answer
