[tex]4y - 6x + 4x^{2}-5(x-y) = 4y-6x+4x^{2}-5x+5y = 4x^{2}-11x+9y[/tex]
[tex]3xy - (-2) -3(2xy-2) = 3xy + 2 - 6xy + 6 = -3xy+8[/tex]
[tex](4a-8b)-(3a-3b)\cdot(-5) =4a-8b+15a - 15b = 19a - 23b[/tex]
[tex]-a(4a-a) - a(2a-5a) = -a\cdot3a - a\cdot(-3a) = -3a^{2}+3a^{2} = 0[/tex]
[tex]-(2+a)-(2a+1)\cdot(-5) = -2-a+10a+5 = 9a+3[/tex]
