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

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 = b - 4ac = 16 - 4×3 = 4 = 2²x1 = ( 4 + 2) / 2 = 3x2 = ( 4 - 2) / 2 = 17) 2x² + x - 3x - 4 = 02x² - 2x - 4 = 0x² - x - 2 = 0D = b² - 4ac = 1 - 4×(-2) = 9 = 3²x1 = ( 1 + 3) / 2 = 2x2 = ( 1 - 3) / 2 = - 18) 2x² - 3x - 4x + 3 = 02x² - 7x + 3 = 0D = b²- 4ac = 49 - 8×3 = 25 = 5²x1 = ( 7 + 5) / 4 = 3x2 = ( 7 - 5)/ 4 = 0,5