(-2x-5)•(0,3x+2,7)=0
-0.6x^2 - 5.4x -1.5x - 13.5=0
-0.6x^2 - 6.9x-13.5=0 \*-1
0.6x^2+6.9x+13.5=0
D= 6.9^2 - 4*0.6*13.5= 47.61 - 32.4=15.21
x1,2= (-6.9+- 3.9)/2*0.6
x1= (-6.9+ 3.9)/ 1.2 = -3/1.2= -2.5
x2= (-6.9- 3.9)/ 1.2= -10.8/1.2= -9
Ответ: x1= -2.5 x2= -9