(2-7х)(5+4х)=0 Решите уравнение!

Question

(2-7х)(5+4х)=0
Решите уравнение!

Answer 1

2-7х=0...........=>....7х=2........=>.......х1=3,5
5+4х=0..................4х=-5..................х2=-1,25

Answer 2

10+8x-35x-28x^2=0
-28x^2-27x+10=0 | * (-1)
28x^2 + 27x - 10=0
Д = 729 +1120=1849
x1= -27+46/56= 19/56
x2= -27-46/56= -73/56