Question

Решите пжлст 2х2+5х-7=0

Answer 1

если 2x2+5x-7=9

4x+5x-7=0

9x-7=0

9x=7

x=7/9

если степень 

2x^2 - 5x - 7 = 0

2x^2 - 5x - 7 = 0

D = 5²-482*(-7)=25 + 56 = 81 = 9^2

x=-5±9/4

x1=- 7/2

x2=1