4n + 1= 25 how do I solve this and show my work?

What is the best way to answer questions with a x expression in the question. for example 3x + 10x=?

What is the product? a-3/15a × 5/a-3

Which statements about the system are true? check all that apply. y =1/3 x – 4 3y – x = –7 the system has one solution. the system consists of parallel lines. both lines have the same slope. both lines have the same y–intercept. the equations represent the same line. the lines intersect.