1) 14-x=-28 2) x-9=-3,1 3) -2,1-x=-2 4) (x-5)(x+1)=0 - вопрос №412222611428293132124510528430 от aleksandrkozlov1 06.10.2020 02:13

Question

Алгебра: 1) 14-x=-28 2) x-9=-3,1 3) -2,1-x=-2 4) (x-5)(x+1)=0 5) (2x-8)(4x+3)=0 решить уравнения, это !

aleksandrkozlov1 · Answer

1) 14 - x = - 28- x = - 28 - 14- x = - 42x = 422) x - 9 = - 3,1x = - 3,1 + 9x = 5,93)  - 2,1 - x = - 2- x = - 2 + 2,1- x = 0,1x = - 0,14) ( x - 5)( x + 1) = 0x² + x - 5x - 5 = 0x² - 4x - 5 = 0D = b² - 4ac = ( - 4)² - 4 × 1 × ( - 5) = 16 + 20 = 36 = 6²x₁ = 4 + 6 / 2 = 10/2 = 5x₂ = 4 - 6 / 2 = - 2/2 = - 15) ( 2x - 8)( 4x + 3) = 08x² + 6x - 32x - 24 = 08x² - 26x - 24 = 0D = b² - 4ac = ( - 26)² - 4 × 8 × ( - 24) = 676 + 768 = 1444 = 38²x₁ = 26 + 38 / 16 = 64 / 16 = 4x₂ = 26 - 38 / 16 = - 12/ 16 = -...