Answer:
(y + 1)
Step-by-step explanation:
Given
5y² + 4y - 1
To factorise the quadratic
Consider the factors of the product of the coefficient of the y² term and the constant term which sum to give the coefficient of the y- term
product = 5 × - 1 = - 5 and sum = + 4
The factors are + 5 and - 1
Use the factors to split the y- term
5y² + 5y - y - 1 ( factor the first/second and third/fourth terms )
= 5y(y + 1) - 1(y + 1) ← factor out (y + 1) from each term
= (y + 1)(5y - 1)
