1) 7x-3(x+8) = 7x-3x-24 = 4x-24
2) 2x(x-3)+4(3x+2) = [tex]2x^{2}[/tex]-6x+12x+8 = [tex]2x^{2}[/tex]+6x+8
3) -4x(5+2x)-2x(-2x+5) = -20x-[tex]8x^{2}[/tex]-2x(-2x+5) = -20x-[tex]8x^{2}[/tex]+[tex]4x^{2}[/tex]-10x = -30x-[tex]8x^{2}[/tex]+[tex]4x^{2}[/tex] = -30x-[tex]4x^{2}[/tex]
4) 3x-[tex]\frac{6x+9}{3}[/tex] = 3x-[tex]\frac{3(2x+3)}{3}[/tex] = 3x-(2x+3) = 3x-2x-3 = x-3
5) ab(-[tex]a^{2}[/tex]+b)-(b-[tex]a^{2}[/tex]+ab)*b = -[tex]a^{3}[/tex]b+[tex]ab^{2}[/tex]-([tex]b^{2}[/tex]-[tex]a^{2}b[/tex]+[tex]ab^{2}[/tex]) = -[tex]a^{3}[/tex]b+[tex]ab^{2}[/tex]-[tex]b^{2}[/tex]+[tex]a^{2} b[/tex]-[tex]ab^{2}[/tex] = -[tex]a^{3}b[/tex]-[tex]b^{2}[/tex]+[tex]a^{2} b[/tex]
