If (f(x)=25+6x), what is the value of (f(x+4)-f(x))?
Answer and explanation
Correct answer: 24
First, f(x+4)=25+6(x+4)=25+6x+24. Therefore, f(x+4)-f(x)=(25+6x+24)-(25+6x)=24. Hence, 24 is the correct option. 18 may seem tempting, but an increase of 4 units at a rate of 6 gives 6×4=24. Exam tip: For a linear function ax+b, increasing x by h always changes the function by ah.
Frequently asked questions
What is the correct answer to this question?
24
Why is this the correct answer?
First, f(x+4)=25+6(x+4)=25+6x+24. Therefore, f(x+4)-f(x)=(25+6x+24)-(25+6x)=24. Hence, 24 is the correct option. 18 may seem tempting, but an increase of 4 units at a rate of 6 gives 6×4=24. Exam tip: For a linear function ax+b, increasing x by h always changes the function by ah.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear growth and decay.
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