(3b -2)(4b-2)= ?

(3b -2)(4b-2)=12b²-6b-8b+4=12b²-14b+4

12b²-14b+4=0

D = b 2 - 4ac = 4, D > 0 =>2 вещественных решения, √D = 2

x 1 = -b + √D/2а = 14 + 2/2 × (12) =  0,6667

x 2 = -b - √D/2а = 14 - 2/2 × (12) =  0,5