Question

Solve. 2x2 – 8x – 12 = 0

x = 1 ± 2

x = 2 ±

x = 2 ±

x = 2 ± 2

Answer 1

By factoring, we obtain:

2(x² - 4x - 6) = 0

Since the polynomial is unfactorable, we can apply quadratic formula x = (-b ± √(b² - 4ac))/2a, along with ax² + bx + c = 0, to obtain:

a = 1
b = -4
c = -6

x = (-(-4) ± √((-4)² - 4*1*-6))/(2*1)
==> (4 ± √(16 + 24))/2
==> (4 ± √40)/2
==> (4 ± √(10*4))/2 . . . . . . . . . . . . . . .Note that √4 = 2.
==> (4 ± 2√10)/2 . . . . . . . . . . . . . . . . Factor
==> 2(2 ± √10)/2 . . . . . . . . . . . . . . . . Reduce
==> 2 ± √10

Therefore, x = 2 ± √10

Answer 2

yeah @dusty is right