`x(x-2)-5(x-1)(x+9)`
`= x^2 - 2x - 5(x-1)(x+9)`
`= x^2 - 2x - 5x^2 - 40x + 45`
`= -4x^2- 42x+45`
`(4x+3)(2-y)+(y+1)(x-5)`
`= 8x - 4xy + 6 - 3y + (y+1)(x-5)`
`= 8x - 4xy + 6 -3y+xy-5y+x-5`
`= 9x - 3xy + 1 - 8y`
`(x+5)(x-1) + (2x-3)(x-7) - 3(x-1)(x+1)`
`= x^2 + 4x- 5+(2x-3)(x-7)-3(x-1)(x+1)`
`= x^2 + 4x - 5 + 2x^2 - 17x + 21-3(x-1)(x+1)`
`= x^2 + 4x - 5 + 2x^2 - 17x + 21 - 3x^2 + 3`
`= -13x + 19`