Math Problem Statement
What is f(a+b) if f(x) = 3x^2 - 2x + 5? What is f(-3/5) if f(x) = x^3 - 3x^2 + x - 5? What is f(3) if f(x) = 4x^5 - x^3 + 5x^2 + 3x/2 - 1/2?
Solution
Let's solve each problem one by one from the image you've uploaded:
Problem 4:
We are given f(x)=3x2−2x+5. The goal is to find f(a+b).
- Substitute a+b into the function for x:
f(a+b)=3(a+b)2−2(a+b)+5
- Expand the expression:
(a+b)2=a2+2ab+b2
So, we get:
f(a+b)=3(a2+2ab+b2)−2(a+b)+5
- Distribute the constants:
f(a+b)=3a2+6ab+3b2−2a−2b+5
Thus, the final expression for f(a+b) is:
f(a+b)=3a2+6ab+3b2−2a−2b+5
Problem 5:
We are given f(x)=x3−3x2+x−5 and asked to find f(−53).
- Substitute x=−53 into the function:
f(−53)=(−53)3−3(−53)2+(−53)−5
- Calculate each term:
(−53)3=−12527
(−53)2=259,3(259)=2527
(−53)=−53
- Combine the terms:
f(−53)=−12527−2527−53−5
- Convert all terms to a common denominator (125):
f(−53)=−12527−125135−12575−125625
- Combine the fractions:
f(−53)=125−27−135−75−625=125−862
Thus, the result is:
f(−53)=−125862
Problem 6:
We are given f(x)=4x5−x3+5x2+23x−21 and asked to find f(3).
- Substitute x=3 into the function:
f(3)=4(3)5−(3)3+5(3)2+23(3)−21
- Calculate each term:
35=243,4(243)=972
33=27
32=9,5(9)=45
23(3)=29
21=21
- Combine the terms:
f(3)=972−27+45+29−21
f(3)=990−27+28
f(3)=963+4=967
Thus, the result is:
f(3)=967
Would you like more details on any of the solutions? Here are 5 related questions:
- How can we apply function transformations to evaluate values like f(a+b) for more complex functions?
- What steps can be taken to simplify polynomial functions further?
- How do we handle fractional exponents in polynomial evaluation?
- What are the general methods for solving polynomials with multiple variables?
- How does substitution work in higher-degree polynomials?
Tip: Always check your calculations step-by-step, especially when dealing with fractional powers or combining terms from different denominators.