a) x²+9x+18=0

x1+x2= -9

x1*x2= 18

-3+x2= -9

x2= -9+3

x2= -6

х1= -3

б) -2х²+2х+24=0 /2

-х²+х+12=0 *(-1)

х²-х-12=0

x1+x2=1

x1*x2= -12

x1-3=1

x1= 4

х2= -3