Question

Almost done help......

Answer 1

Answer:

x = 1 + ( √ 10 )/ 2, or x = 1 - ( √ 10 )/ 2; Option A

Step-by-step explanation:

See steps below;

I would prefer answering this question by completing the square, rather than applying a quadratic formula;

3x^2 - 6x - 12 = 0, ⇒ Add 12 to either side,

3x^2 - 6x = 12, ⇒ Divide either side by 3,

x^2 - 2x = 4, ⇒ Write the equation in the form x^2 + 2ax + a^2 = (x + a)^2,

x^2 - 2ax + a^2 = 4 + a^2, ⇒ Solve for a

2ax = -2x,

a = - 1, ⇒ Substitute value of a,

x^2 - 2x + 1 = 4 + 1,

( x - 1 )^2 = 5, ⇒ Solve for x,

x = √5 + 1, and x = - √5 + 1,

In other words; Solution : x = 1 + ( √ 10 )/ 2, or x = 1 - ( √ 10 )/ 2; Option A