What method to use . . . .?

Hi,

We would use a method called "Completing square root".

And to find the completed root is (-b /2)^2

Let have a look at your question.

x² - 2x +5 = 0

Subtract 5 from both side

x² - 2x = -5

Find the completed square root and it to the equation.

(-b /2)^2 = [-(-2) /2]^2 = 1^2 = 1

So,

x² - 2x + 1 = -5 + 1

(x - 1)² = -4

..............___

x - 1 = ±\/ -4

..............______

x - 1 = ±\/ -1 * 4 (sqrt of -1 = i)

x - 1 = ±2i

Add 1 to both sides.

x = ±2i + 1 <<< ANSWER!

I hope that helps!!! :-)

Your options are the quadratic formula and completeing the square.

This one is easily done completing the square.

x² - 2x = -5

x² - 2x + 1 = -5 + 1

(x - 1)² = -4

x -1 = ± 2i

x = 1 ± 2i

you can use the quadratic formula:

x = [ - b +- sqrt(b^2 - 4ac) ] / 2a

Those that call this the quadratic equation are wrong. A quadratic equation is one in the form (ax^2 + bx + c).

either copleting thesquare or quadratic formula

(x-1)^2 + 4 = 0---->x = 1+2i, 1-2i

hi since there is no GCF find the product and sum. the product is 5 the sum is -2. this is prime. since that wont work use quadratic formula

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you use the quadriatic equation:

when ax^2 + bx + c = 0

then:

x = (b +/- (b^2 - 4ac)^1/2) / 2a

in your case

a = 1

b = -2

c = 5

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