Here, we can use factoring decomposition; determine two values in which the product is 20 and the sum is 12. They are 2 and 10, so split 12x into 2x and 12x!
4x² + 2x + 10x + 5 = 0
Factor like terms..
2x(2x + 1) + 5(2x + 1) = 0
Group the common factors of 2x + 1 and collect the terms..
(2x + 1)(2x + 5) = 0
Finally, by zero-product property:
2x + 1 = 0 and 2x + 5 = 0
2x = -1 and 2x = -5
x = {-½, -5/2}
I hope this helps!
