In a video game, a player's score on level
n is given by
s(n)=n2+2n+10. After an update, the level counter starts at 5 (instead of 0), and all scores increase by 50 points. Write the new score function.
h=5,k=50 The level counter starting at 5 represents a horizontal shift of h=5 to the right; the 50-point bonus is a vertical shift of k=50 upward.
snew(n)=(n−5)2+2(n−5)+10+50 Apply the formula: replace each instance of n with (n−5) in s(n)=n2+2n+10, then add the vertical shift k=50.
(n−5)2=n2−10n+25 Expand (n−5)2 using (a−b)2=a2−2ab+b2; here a=n and b=5, so n2−2(5)n+25=n2−10n+25.
2(n−5)=2n−10 Distribute the 2 across the binomial: 2⋅n−2⋅5=2n−10.
snew(n)=n2−10n+25+2n−10+10+50 Substitute the expanded expressions from the previous steps into the full formula.
snew(n)=n2+(−10+2)n+(25−10+10+50) Collect like terms: combine all n2 terms, all n terms (−10n+2n), and all constants.
snew(n)=n2−8n+75 Simplify: −10+2=−8 and 25−10+10+50=75.
This problem demonstrates that translation applies to any function, not just simple ones. Understanding that 'the level counter starts at 5' means replacing the variable with (n−5), and carefully expanding all instances of n in multi-term functions, are essential skills for word-problem applications of translation.