Question

Solve x2 + 2x = 4 for x by completing the square. x equals plus or minus square root of 5 plus 1 x equals plus or minus square root of 5 minus 1 x = 1 x = 3

Answer 1

Answer:

x equals plus or minus square root of 5 minus 1

Step-by-step explanation:

we have

$x^{2} +2x=4$

Divide by 2 the coefficient of the x-term

$2/2=1$

squared the number

$1^2=1$

Adds both sides

$x^{2} +2x+1=4+1$

$x^{2} +2x+1=5$

Rewrite as perfect squares

$(x+1)^{2}=5$

take the square root both sides

$x+1=(+/-)\sqrt{5}$

$x=(+/-)\sqrt{5}-1$

therefore

x equals plus or minus square root of 5 minus 1