Muft Shiksha
Update

Muft Shiksha™ एक 100% Free Education Portal है 🇮🇳, जिसका उद्देश्य Class 9–12 के हर विद्यार्थी तक High-Quality Education को पूरी तरह मुफ्त पहुँचाना है। 🇮🇳 हम मानते हैं कि अच्छी शिक्षा किसी student की आर्थिक स्थिति पर निर्भर नहीं होनी चाहिए। 🇮🇳 हर विद्यार्थी को वही Quality Study Material, MCQs, Quizzes, Exam Preparation, Concept-Based Learning और Bilingual Support मिलना चाहिए, जो आमतौर पर महंगी Coaching या Premium Platforms में मिलता है। Muft Shiksha™ 🇮🇳 इसी सोच के साथ बनाया गया है

Subjects
Class 9MathematicsIntroduction to PolynomialsLinear growth and decayMediumLevel 36
0 reads0 ratings0 helpful

If (f(x)=4x+9), what is the value of (f(5)+f(7))?

Advertisement

Answer and explanation

Correct answer: 66

Given \(f(x)=4x+9\), \(f(5)=4\times5+9=29\) and \(f(7)=4\times7+9=37\). Therefore, \(f(5)+f(7)=29+37=66\). A value such as 72 can result from incorrect substitution while evaluating the function. Exam tip: evaluate each function value separately before adding them.

Related tags

PolynomialsFunction EvaluationLinear FunctionSubstitutionAlgebraic Expressions

Frequently asked questions

What is the correct answer to this question?

66

Why is this the correct answer?

Given \(f(x)=4x+9\), \(f(5)=4\times5+9=29\) and \(f(7)=4\times7+9=37\). Therefore, \(f(5)+f(7)=29+37=66\). A value such as 72 can result from incorrect substitution while evaluating the function. Exam tip: evaluate each function value separately before adding them.

Which subject and chapter does this question cover?

This is a Class 9 Mathematics question. Chapter: Introduction to Polynomials. Topic: Linear growth and decay.

Was this question useful?

No ratings yetWrite a review / Rate this question

Student Reviews

No published reviews yet.

KEEP PRACTISING

10 more MCQs
  1. 1If the height of a plant is (h(t)=20+3t) cm, what type of change does it show?
  2. 2If the amount of water is (W(t)=50-4t) litres, what type of change is it?
  3. 3In the linear rule (C(d)=15+2d), what is the initial value?
  4. 4In the linear rule (P(t)=80-5t), what is the rate of change per unit?
  5. 5If (S(t)=10+6t), what will be the value of (S(t)) at (t=4)?
  6. 6If (M(t)=90-7t), what is the value of (M(t)) at (t=5)?
  7. 7Books in a library increase according to (B(n)=100+8n). What does the coefficient of (n) show?
  8. 8If water left in a tank is (L(t)=60-3t) litres, how much water was there at (t=0)?
  9. 9Which rule represents linear growth?
  10. 10Which rule represents linear decay?
Advertisement