1)3х-4=8
2)12-2Х=-10
3)2Х+3=10
4)14Х-7=28
5)(Х-3)(15-Х)=0
6)(2Х-20)(3+3Х)=0
7)(12-3Х)(25-5Х)=0

1) 3x - 4 = 83x = 12x = 42)12 - 2x = - 10- 2x = - 22x = 113)2x + 3 = 102x = 7x = 3,54) 14x - 7 = 2814x = 35x = 2,55) (x - 3)(15 - x) = 015x - x² - 45 + 3x = 0- x² + 18x - 45 = 0x² - 18x + 45 = 0D = b² - 4ac = 324 - 4×45 = 324 - 180 = √144= 12x₁ = 18 + 12/2 = 15x₂ = 18 - 12/2 = 36) (2x - 20)(3 + 3x) = 06x + 6x² - 60 - 60x = 06x² - 54x - 60 = 0D = 2916 - 4×6 × ( - 60) = 2916 + 1440 = 4356x₁ = 54 + 66/ 12 = 10x₂ = 54 - 66/12 = - 17)( 12 - 3x)(25 - 5x) =0300 -  60x - 75x + 15x² = 015x² - 135x + 300 = 0D = 18225 - 4 × 15 × 300 = 18225 - 18000 = √225 = 15x₁ = 135 + 15/30 = 5x₂ = 135 - 15/30 = 4