/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 96 Find \(a\) if \(f(a)=9\) and \(f... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Find \(a\) if \(f(a)=9\) and \(f(x)=2 x^{2}+1\)

Short Answer

Expert verified
a = 2 and a = -2

Step by step solution

01

- Understand the function

We are given the function \( f(x) = 2x^2 + 1 \) and need to find \( a \) such that \( f(a) = 9 \).
02

- Set up the equation

Since we need to find \( a \) such that \( f(a) = 9 \), we set up the equation: \( 2a^2 + 1 = 9 \).
03

- Solve for \( a \)

Solve the equation: \[ 2a^2 + 1 = 9 \] Subtract 1 from both sides: \[ 2a^2 = 8 \] Divide both sides by 2: \[ a^2 = 4 \] Take the square root of both sides: \[ a = \pm 2 \]
04

- Identify the solutions

Both \( a = 2 \) and \( a = -2 \) satisfy the equation \( 2a^2 + 1 = 9 \). So, the solutions are \( a = 2 \) and \( a = -2 \).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

headline of the respective core concept
Function evaluation is a fundamental concept in algebra. It involves substituting a given value into a function to find the corresponding output. For this exercise, we have the function \( f(x) = 2x^2 + 1 \). The problem asks us to find the value of \(a\) such that \( f(a) = 9 \). By plugging \(a\) back into the function, we establish an equation to solve for \(a\). This step is crucial as it translates the problem from a verbal statement into a manageable algebraic form.
headline of the respective core concept
Quadratic equation solving is essential when dealing with functions like \( f(x) = 2x^2 + 1 \). To find \(a\) for which \( f(a) = 9 \), we set up the equation: \(2a^2 + 1 = 9\). This is a quadratic equation in standard form \( Ax^2 + Bx + C = 0 \). Solving for \(a\) involves isolating \(a^2\) by first subtracting 1 from both sides: \( 2a^2 = 8 \). Then we divide by 2: \( a^2 = 4 \). Finally, taking the square root of both sides, we get two possible solutions: \(a = 2\) or \(a = -2\). Quadratic equations result in two solutions due to the square root property.
headline of the respective core concept
Algebraic manipulation is a key skill in simplifying and solving equations. In this exercise, once we set up the quadratic equation \(2a^2 + 1 = 9\), we use algebraic steps to isolate the variable \( a \). These steps include operations like addition, subtraction, multiplication, division, and taking square roots. Each step adheres to the properties of equality, ensuring the equation remains balanced. For instance, subtracting 1 from both sides simplifies the equation to \(2a^2 = 8\). Dividing both sides by 2 further simplifies it to \(a^2 = 4\). Taking the square root of both sides gives us the solutions \( a = \pm 2 \). These manipulations help us solve the equation accurately.

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