Answer:
x = -
, x = 2
Explanation:
Given
8x² - 14x - 4 = 0 ( divide through by 2 to simplify )
4x² - 7x - 2 = 0
To factorise the quadratic
Consider the factors of the product of the coefficient of the x² term and the constant term which sum to give the coefficient of the x- term
product = 4 × - 2 = - 8 and sum = - 7
The factors are - 8 and + 1
Use these factors to split the x- term
4x² - 8x + x - 2 = 0 ( factor the first/second and third/fourth terms )
4x(x - 2) + 1(x - 2) = 0 ← factor out (x - 2) from each term
(x - 2)(4x + 1) = 0
Equate each factor to zero and solve for x
4x + 1 = 0 ⇒ 4x = - 1 ⇒ x = -
x - 2 = 0 ⇒ x = 2