Question

Solve the following equation algebraically: x^2=20

Answer 1

Explanation:

x² = 20

x² - 20 = 0

x² - (√20)² =0

by identity : a² - b² = ( a - b )( a + b) in this exercice : a = x and b =√20

( x - √20)(x + √20) = 0

x - √20 = 0 or x + √20 = 0

x = √20 or x = - √20

but : 20 = 4×5

20 = √(4×5) =√4×√5 = 2√5

Answer 2

x = ± 2
`√(5)`

Explanation:

Given

x² = 20 ( take the square root of both sides )

x = ±
`√(20)` = ±
`√(4(5))` = ± 2
`√(5)`