A and b because the "product" is the answer to multiplication, and those are the only answers where 7 and n are being multiplied. Answer b is technically more correct than a is because the coefficient should come before the variable.
It’s 4 because if it were on a graph you’d count up 2 over 3 and over 5 up 9
1. As M is the midsegment JM / JK = 1/2
By similar triangles JM/JK = 1/2 = x / 12
2x = 12 so x = 6 answer
2. By the same reasoning as above
x / (x + 9 ) = 8.5 / 17 = 1/2
2x = x + 9
x = 9
Answer x = 9