Final answer:
The process where a number is added and subtracted in a quadratic equation to complete the square is called Completing the square, which is used to convert the equation to vertex form.
Step-by-step explanation:
When changing a standard form equation into vertex form, the process where a number is added and subtracted to complete the square is called Completing the square. This algebraic technique is used to transform a quadratic equation of the form ax^2 + bx + c = 0 into the vertex form a(x-h)^2 + k where (h, k) is the vertex of the parabola represented by the equation.
To complete the square, one typically takes the following steps:
- Divide the quadratic and linear coefficients by a, if a ≠ 1.
- Add and subtract the square of half the coefficient of x inside the parentheses.
- Rearrange the equation to isolate the completed square and the constant terms.
This method is often used as an alternative to the quadratic formula for finding the roots of a quadratic equation or for graphing purposes.