Fill in: survived, violent, sightings, humped, mythical, rustling, torture, dull, glimpse, illusion. 1 Many old castles used to have torture chambers.

1) a) (z+2)(z-2)  б) (3+xy)(3-xy)  в) (1/10x+u^2)(1/10x-u^2)
2)  x2-9y2
3) (c+d)(c-d)/b(c-d) = (c+d)/b
3(x^2-9)/x(3-x) = -3(x+3)(x-3)/x(x-3) = (3х+9)/х