5х^2+3х-8=0 (2х+3)(3х+1)=11х+30 х^2+4х-2=0 решить - вопрос №455804852380233111302420 от lerochek6 19.02.2021 09:33

Question

Алгебра: 5х^2+3х-8=0 (2х+3)(3х+1)=11х+30 х^2+4х-2=0 решить

lerochek6 · Answer

5x² + 3x - 8 = 0D = b² - 4ac = 9 - 4 × 5 × (-8) = 9 + 160 = 169 = 13²x1 = ( - 3 + 13) / 10 = 1x2 = ( - 3 - 13) / 10 = - 1,6ответ: x1 = 1, x2 = - 1,6.(2x + 3)( 3x + 1) = 11x + 306x² + 11x + 3 = 11x + 306x²  + 11x - 11x = 30 - 36x² = 276x² - 27 = 02x² - 9 = 02x² = 9x² = 4,5x1,2 = +/-√4,5ответ: x1,2 = +/-√4,5x² + 4x - 2 = 0D = b² - 4ac = 16 - 4 × (-2) = 16 + 8 = 24x1 = ( - 4 + 2√6) / 2 =-2(2-√6)/2 =  - (2 - √6) = - 2 + √6x2 = ( - 4 - 2√6) / 2 =-2(2 + √6)/2 = -(2 + √6) = - 2 - √6ответ: x1 = - 2 + √6,...