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)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
Гость
Ответ(ы) на вопрос:
Гость
1) 3x - 4 = 8 3x = 12 x = 4 2)12 - 2x = - 10 - 2x = - 22 x = 11 3)2x + 3 = 10 2x = 7 x = 3,5 4) 14x - 7 = 28 14x = 35 x = 2,5 5) (x - 3)(15 - x) = 0 15x - x² - 45 + 3x = 0 - x² + 18x - 45 = 0 x² - 18x + 45 = 0 D = b² - 4ac = 324 - 4×45 = 324 - 180 = √144= 12 x₁ = 18 + 12/2 = 15 x₂ = 18 - 12/2 = 3 6) (2x - 20)(3 + 3x) = 0 6x + 6x² - 60 - 60x = 0 6x² - 54x - 60 = 0 D = 2916 - 4×6 × ( - 60) = 2916 + 1440 = 4356 x₁ = 54 + 66/ 12 = 10 x₂ = 54 - 66/12 = - 1 7)( 12 - 3x)(25 - 5x) =0 300 -  60x - 75x + 15x² = 0 15x² - 135x + 300 = 0 D = 18225 - 4 × 15 × 300 = 18225 - 18000 = √225 = 15 x₁ = 135 + 15/30 = 5 x₂ = 135 - 15/30 = 4
Не нашли ответ?
Ответить на вопрос
Похожие вопросы