Решите уравнение: а)3x^2+9=12x-x^2 б)5x^2+1=6x-4x^2 - вопрос №50752113291225216422334 от sunlight2 23.08.2020 06:40

Question

Алгебра: Решите уравнение: а)3x^2+9=12x-x^2 б)5x^2+1=6x-4x^2 в)x(x+2)-3 г)x(x+3)=4 д)x(x-5)=-4 е)x(x-4)=-3 ж)x(2x+1)=3x+4 з)x(2x-3)=4x-3

sunlight2 · Answer

1) 3x² + 9 - 12x + x² = 04x² - 12x + 9 = 0D = b² - 4ac = 144 - 16×9 = 0x = -b/2ax = 12/8x = 1,52) 5x² + 1 - 6x + 4x² = 09x² - 6x + 1 = 0D = b² - 4ac = 36 - 36×1 = 0x = -b/2ax = 6/18x = 1/33) x² + 2x - 3 = 0D = b² -4ac = 4 - 4×(-3) = 26 = 4²x1 = ( - 2 + 4) / 2 = 1x2 = ( - 2 - 4) / 2 = - 34) x² + 3x -4 = 0D = b²- 4ac = 9 - 4×(-4) = 25 = 5²x1 = ( - 3 + 5) / 2 = 1x2 = ( - 3 - 5) / 2 = - 45) x² - 5x + 4 = 0D = b² - 4ac = 25 - 4×4 = 9 = 3²x1 =( 5 + 3) / 2 = 4x2 = ( 5 - 3) / 2 = 16) x² - 4x + 3 = 0D =...