Second-degree Equation
The second-degree equation is graphically represented as a curve called a parabola.
The parabola can be described by its vertex and leading coefficient as follows:
It's recognized the vertex form of the parabola needs to be expressed as the square of a binomial.
We are given the equation:
We need to complete squares to express the equation in vertex form.
Separate the variable terms from the constant terms:
Now we complete squares on the left side of the equation. We use the following algebraic identity:
It's evident that the second term of our equation has a value of b = 12/2=6
Thus, we need to complete squares by adding 6 squared = 36 as follows:
Applying the above identity:
Since this equation is a different expression of the very same original equation, they have both the same solution.
Answer: The last choice (x-6)^2=21