7 2y 3 )- 9 July 8, 2019 16 32 64 128 8 y 7 )- 3 2y 9 )= 15 7 2y 2 )- 2 3y 3 5 )= 9 2y 7 3 8y 9 14 3y 5 21 9y 7 2y 3 3 y 7 2y 9 2y 3 9y 3y 7 8y 27x 2y 3 9x 4y 7 2y 9x 3 4x 7 3 2y 7 )= 10y 9 2 7+3y=9(y-2 1)