Problem 50 - Elementary Algebra

Question

For the following problems, factor the polynomials, if possible. $$ a^{2}-12 a+36 $$

Step-by-Step Solution

Answer

Answer: The factored form of the given quadratic polynomial is $$(a-6)^2$$.

Step 1: Identify the quadratic polynomial

The given polynomial is: $$ a^2 - 12a + 36 $$

Step 2: Find two numbers whose product is equal to the constant term (36) and whose sum is equal to the linear coefficient (-12)

The two numbers that satisfy this condition are -6 and -6, as their product is 36 and their sum is -12.

Step 3: Apply the factoring method

Since we have found the two required numbers to be -6 and -6, we can now write the given quadratic polynomial in the factored form: $$ a^2 - 12a + 36 = (a-6)(a-6) $$

Step 4: Write down the final factored form

Therefore, the factored form of the given quadratic polynomial is: $$ a^2 - 12a + 36 = (a-6)^2 $$

Key Concepts

Quadratic Polynomials

A quadratic polynomial is an algebraic expression of the form \( ax^2+bx+c \), where \( a \), \( b \), and \( c \) are constants with \( a eq 0 \). The curious thing about quadratic polynomials is that their graph form a parabola, which opens upward or downward depending on the sign of \( a \).

The quadratic polynomial presented in our exercise is \( a^2 - 12a + 36 \), fitting this general structure with \( a=1 \), \( b=-12 \), and \( c=36 \). To understand its characteristics, imagine it visually. Its graph would be a u-shaped curve with a particular point called the vertex. That's where it either reaches its maximum or minimum value. Factoring the quadratic is essential for finding the vertex and understanding the polynomial's nature without completing the square or using the quadratic formula.

Factoring Quadratic Equations

Factoring quadratic equations is like unlocking a puzzle where we look for two binomials that multiply to give the original quadratic expression. The factoring method often used is called 'factoring by grouping'. As shown in the provided solution, we search for two numbers that have a certain relationship to the coefficients of the quadratic polynomial.

Specifically, these two numbers must

• Multiply to give the constant term, \( c \), and,
• Add up to the linear coefficient, \( b \).

Once these numbers are found, as in the case -6 and -6 for \( a^2 - 12a + 36 \), we can rewrite the middle term, \( bx \), using these numbers and then factor by grouping. This process simplifies the expression to the factored form which can then be used for various applications, such as solving quadratic equations or analyzing the function's graph.

Algebraic Expressions

An algebraic expression is a combination of numbers, variables (like \( x \) or \( a \)), and operations (such as addition, subtraction, multiplication, and division). The beauty of algebraic expressions is their ability to generalize mathematical ideas. For instance, the expression \( a^2 - 12a + 36 \) not only represents specific numbers when \( a \) is given a value but also encapsulates the relationship between those numbers.

An important aspect of handling algebraic expressions is simplification, which often involves factoring. By turning a complicated expression into a product of simpler ones, we can make difficult problems more manageable. This technique is not only fundamental in solving equations but also in understanding more complex concepts in calculus and beyond. A solid grasp of algebraic expressions and their manipulation is absolutely central to any study of mathematics.