I don’t know what I’m doing

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.

What values of x satisfy the inequality x^2-9x< 0? how is your answer shown on the graph?

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.