6 5y 9 =- 3 July 8, 2019 16 32 64 128 5y 9 3y 6 4 5y 9 )-( 6 2 3 1y 6 5y =- 9 4 3y 13 6x 5y 9 3x 2y 6 =- 1 6 5y =- 9 4x 3y 13 6xy - 4y + 6 - 9x