Bruno needs to solve the equation x2 + 6x – 8 = 0 by completing the square. Which pair of steps is the most efficient way to begin?

Question

asked Feb 5, 2021 168k views

1 Answer

Sanny Sin · Answer 1 · 2021-02-12T06:20:20+0000

There are probably some choices we're not being shown, but let's just do the whole procedure.

x² + 6x - 8 = 0

Step one: move the 8 to the other side.

x² + 6x = 8

Step two: add (6/2)²=9 to both sides.

x² + 6x + 3² = 8 + 9

Step three: Factor

(x + 3)² = 17

Step four: take the square root

x + 3 = ±√17

Step five: Solve for x,

x = -3 ± √17