Solve Quadratic by Square Root

Find the zero(s) by taking square roots.

When solving a quadratic equation, when do you use the plus or minus (±) symbol?

• After taking the square root of both sides

• After adding the square to both sides

• After taking half of b

• After setting the equation equal to zero

2x²=100

• x = √25

• x = ±5√2

• x = √100

• x = ±√5

(x - 2) ² = 9

• ± 3

• 5  or  -1

• -5  or  1

• ± 9

x² + 1 = 9

• ± √8

• ± 4

• ± 8

• ± 3

16a² - 9 = 0

• a = ^-3/₄, ³/₄

• a = ^-4/₃, ⁴/₃

• a = ^-9/₁₆, ⁹/₁₆

• a = ^-16/₉, ¹⁶/₉