Going by what I was taught in chemistry, there would only be 1.
D. Because you're multiplying 3 by a number which is what the variable represents (n), then you're just adding 7 to that which equals 19 all together. It all translates to 3n+7=19.

Since we are solving the quadratic equation because the highest degree in the equation is second. We arrange in the form of ax²+bx+c = 0.

Combine like terms.

Solve the equation by factoring.

Hence the values of x that make f(x) = g(x) are -3 and 1.
Answer
Let me know if you have any doubts!
Four times the sum of n plus six
A non-terminating and no -repeating decimal