Question

Solve by completing the square


`x ^(2) + 10x + 14 = - 7`
what is another method could you use to solve this quadratic? explain ​

Answer 1

see explanation

Explanation:

Given

x² + 10x + 14 = - 7 ( subtract 14 from both sides )

x² + 10x = - 21

To complete the square

add ( half the coefficient of the x- term )² to both sides

x² + 2(5)x + 25 = - 21 + 25

(x + 5)² = 4 ( take the square root of both sides )

x + 5 = ± 2 ( subtract 5 from both sides )

x = - 5 ± 2

x = - 5 - 2 = - 7, or x = - 5 + 2 = - 3

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The equation can also be solved by factoring

x² + 10x + 14 = - 7 ( add 7 to both sides )

x² + 10x + 21 = 0 ← in standard form

(x + 7)(x + 3) = 0 ← in factored form

Equate each factor to zero and solve for x

x + 7 = 0 ⇒ x = - 7

x + 3 = 0 ⇒ x = - 3