Question

For which equation does it make the most sense to solve by completing the square?

5x² + 3x = 9

3x2−x+17=0

x² + 20x = 52

x2−8=1

Answer 1

x² + 20x = 52. Why? Completing the square is easier for this equation in comparison to completing the square for the first two equations.

x^2-8=1 becomes x^2=9, so that x=plus or minus 3. Why bother with completing the square here?

x^2 + 20x = 52
x^2 + 20x + 100 - 100 = 52
(x+10)^2 = 152

taking the sqrt of both sides:

x+10 = plus or minus sqrt(152) (and so on).

Answer 2

Explanation: