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

5x² + 3x - 8 = 0
D = b² - 4ac = 9 - 4 × 5 × (-8) = 9 + 160 = 169 = 13²
x1 = ( - 3 + 13) / 10 = 1
x2 = ( - 3 - 13) / 10 = - 1,6
ответ: x1 = 1, x2 = - 1,6.

(2x + 3)( 3x + 1) = 11x + 30
6x² + 11x + 3 = 11x + 30
6x²  + 11x - 11x = 30 - 3
6x² = 27
6x² - 27 = 0
2x² - 9 = 0
2x² = 9
x² = 4,5
x1,2 = +/-√4,5
ответ: x1,2 = +/-√4,5

x² + 4x - 2 = 0
D = b² - 4ac = 16 - 4 × (-2) = 16 + 8 = 24
x1 = ( - 4 + 2√6) / 2 =-2(2-√6)/2 =  - (2 - √6) = - 2 + √6
x2 = ( - 4 - 2√6) / 2 =-2(2 + √6)/2 = -(2 + √6) = - 2 - √6
ответ: x1 = - 2 + √6, x2 = - 2 - √6.