You are using synthitic division to divide a cubic by a linear term. Should not your result be a quadratic? None of the suggestions made so far are correct.
I might also point out that if you divide a polynomial, P(x), by the linear term x-a, the remainder is P(a). What do you get if you set x= 5 in
x^{3}- 4x+ 1?
We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling We Value Civility
• Positive and compassionate attitudes
• Patience while debating We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving