Lesson 4.2: Solving Quadratics by Taking Square Roots and Completing the Square

Question 1

Square Root

Answer 1

when multiplied by itself produces another number; The square root of a number n
is any number s such that s^2=n

Question 2

Radical

Answer 2

symbol for square root is the radical sign, or √

Question 3

Radicand

Answer 3

number under the radical is called the radicand

Question 4

Imaginary Number

Answer 4

i represents an imaginary number; i = the square root of −1. We can also say that i^2=−1

Question 5

Complex Number

Answer 5

sum of a real number and an imaginary number; one of the form a+bi
where a and b are real numbers (a is the real part of the complex number, and bi is the imaginary part of the complex number)

Question 6

Completing the Square

Answer 6

Completing the square lets you rewrite a quadratic expression so that it contains a perfect square trinomial that you can factor as the square of a binomial. the square of a binomial takes one of the following forms:

(a+b)^2=a^2+2(ab)+b^2

(a−b)^2=a^2−2(ab)+b^2