(3х+5)(4х-1)=(6х-3)(2х+7) (5х-1)(2-х)=(х-3)(2-5х) (5х+1)(2х-3)=(10х-3)(х+1) (7х-1)(х+5)=(3+7х)(х+3)

1) 12x²-3x+20x-5 = 12x²+42x-6x-21
17x-5=36x-21
-19x=16
x=- 16/19
2)
10x-5x²-2+x=2x-5x²-6+15x
11x-2=17x-6
-6x=-4
x=2/3
3)
10x²-15x+2x-3=10x²+10x-3x-3
-13x-3=7x-3
-20x=0
x=0
4)
7x²+35x-x-5=3x+9+7x²+21x
34x-5=24x+9
10x=14
x=1,4