Question

x² − 12x + 36 = 0

Solutions?

Answer 1

Factors of 36 that add up to -12

-6 and -6

(x − 6)(x − 6)

Set them both to equal 0 and solve for x

x - 6 = 0

x - 6 = 0

x = 6

x = 6

Answer 2

x² - 12x + 36 = 0
We know this is in standard form so we can use the quadratic formula. Indeed like a previous solution posted you can use factors, that is quicker but this will always work so let's see.

Now let's fill the gaps in the formula 

x = 12 +- square root of (144 - 4(1)(36) )/ 2 

X = 12 +- square root of (144 - 144) / 2 

X = 12 / 2 

X = 6