Hello,
If we want to factor the expression, we have to solve
3x² + 10x + 8 = 0
a = 3 ; b = 10 ; c = 8
∆ = b² - 4ac = 10² - 4 × 3 × 8 = 4 > 0
x1 = (-b - √∆)/2a = (-10 - 2)/6 = -12/6 = -2
x2 = (-b + √∆)/2a = (-10 + 2)/6 = -8/6 = -4/3
Factor :
a (x - x1)(x - x2)
= 3(x + 2)(x + 4/3)
= (x + 2)(3x + 4)