a) (x-3)(5-x) -2 = (2-x)(x-4) +3
5x-x²-15+3x-2 = 2x -8-x²+4x
5x-x²+3x-2x+x²-4x = -8 +15+2
6x = 9 /:6
x = 1,5
b) (6-x)(x+2) + (x+3)(x-4) = 2x +5
6x+12-x²-2x + x²-4x+3x-12 = 2x +5
2x=5 /:2
x=2,5
c) (x-5)(x+2) - (3-x)(2-x) = x -12
x²+2x-5x-10 - 6 + 3x +2x -x² = x-12
15x = 12 /:15
x=0,8
d) (2x - 5)(x+1) -2 =(1-x)(8-2x) + 2x
2x²+2x-5x-5-2 = 8x-2x-8x+2x²
-x=7 /:(-1)
x=-7