Answer:
see explanation
Explanation:
Given
4x² + 21x + 27 = 0
Consider the factors of the product of the x² term and the constant term which sum to give the coefficient of the x- term.
product = 4 × 27 = 108 and sum = 21
The factors are 12 and 9
Use the factors to split the x- term
4x² + 12x + 9x + 27 = 0 ( factor the first/second and third/fourth terms )
4x(x + 3) + 9(x + 3) = 0 ← factor out (x + 3) from each term
(x + 3)(4x + 9) = 0
Equate each factor to zero and solve for x
x + 3 = 0 ⇒ x = - 3
4x + 9 = 0 ⇒ 4x = - 9 ⇒ x = - 2.25
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Following the same method as the previous question
Given
6x² + 43x - 40 = 0
Consider the factors of the product of the x² term and the constant term which sum to give the coefficient of the x- term
product = 6 × - 40 = - 240 and sum = + 43
The factors are + 48 and - 5, thus
6x² + 48x - 5x - 40 = 0
6x(x + 8) - 5(x + 8) = 0
(x + 8)(6x - 5) = 0
x + 8 = 0 ⇒ x = - 8
6x - 5 = 0 ⇒ 6x = 5 ⇒ x =
