Algebra Demystified 2nd Ed

362 alGEbra De mystif ieD

Solve the quadratic equation by extracting roots.

25 – x^2 = 0

25 = x^2

±5 = x

Solve the quadratic equation by extracting roots.

4 x^2 = 49

x^249

4

 = 

x = ±^49

4

x = ±^7

2

In the next example, we need to simplify the solution. Recall that a is not

simplified if the number a has a perfect square as a factor.

3 x^2 = 36

x^2 = 12

x = ±1 2

x = ± 43 ⋅  = ±()() 43  = ± 23

PRACTICE

Solve the quadratic equation by extracting roots.

1. x^2 – 81 = 0


2. 64 – x^2 = 0


3. 4x^2 = 100


4. 2x^2 = 3


5. –6x^2 = –80

✔SOLUTIONS

1. x^2 − 81 = 0
   x^2 = 81
   x = ± 9

PRACTICE

Solve the quadratic equation by extracting roots.

1. xxx^22 – 81 = 0

PRACTICE

Solve the quadratic equation by extracting roots.