10а^2-6a+5ab-3b = 2a(5a-3)+b(5a-3) = (5a-3)(2a+b) = 2a+b
5a^2- 8a+3 5a^2-8a+3 (a-1)(5a-3) a-1
5a^2-8a+3=/(не равен)0
D1=16-15=1
x1=1
x2=3/5
2*(х-3)=3*(4-х)+5
2х-6=12-3х+5
2х+3х=12+5+6
5х=23
х=23/5
х=4,6