Question

Determine the factors of x2 − 12x − 20.

Answer 1

(x-10)(x-2)

Formula:

a^{2} - b^{2} = (a-b)(a+b)

Explanation:

(x-6)^2-4^2

Then we can simplify to, (x-6-4)(x-6+4)

Which comes to your answer, (x-10)(x-2)

Answer 2

Explanation:

x² − 12x − 20 = 0

a = 1; b = (-12); c = (-20)

b²-4ac = (-12)² - 4 * 1 * (-20) = 144 + 80 = 224

√b²-4ac = √ 224 = √ 2*2*2*2*2*7 = 2*2*√(2*7) = 4√14

delta = -b ± √b²-4ac / 2a

= -(-12) ± 4√14

2 * 1

= (12 ± 4√14)/2

= 2 ( 6 ± 2√14) / 2

= 6 ± 2√14

x = 6 + 2√14; x = 6 - 2√14