[tex]-7a - 4a + 4 = -11a + 4\\\\4a - 7a + a - 3a = -5a\\\\9x+3-10x+6x = 5x + 3\\\\-4a + 5 - 6a - 7 + 8a = -2a-2\\\\7x+3y-3x+5y-11x = -7x+8y\\\\-5a+8-6b+12a-15+13b = 7a+7b - 7\\\\17x-12+4+8y-9x-x+8 = 7x+8y[/tex]
[tex]-4a +2b-3c+b-7a+9b+8c = -11a+12b +5c\\\\4z-5y+3-7z+13y = 8y -3z + 3\\\\-7c+2d + 4 - 8c - 5d + 7 = -15c - 3d + 11\\\\8a - 4b + 7 + 3 - 15a + 17b = -7a + 13b + 10\\\\7x-3y+2z-6z+8x-4y+6z = 15x-7y+2z\\\\-6a+2b-3c-2a+b-c-7a = -15a +3b -4c[/tex]