Im pretty sure it's 17.5 since 35 is odd.
The answer is (7,6)
This is because a midpoint is in the exact middle, meaning that both sides are an equal distance away. You can find this by fining the difference between the two corresponding coordinates then adding that difference to the midpoint and that will give you your other endpoint.
Hope this helped !!
Are you finding m? If so here is the answer:
75 = -5(3 + 6m)
Distribute:
75 = -15 - 30m
Add 15 to both sides:
75 = -15 - 30m
+15 +15
90 = -30m
Divide by -30 on both sides:
90/-30 = (-30m)/-30
You should get: m = -3