Which pair of expressions below are equivalent?

n, plus, p, plus, p, plus, p, and , 4, n, pn+p+p+p and 4np
3, left bracket, 9, n, plus, 10, right bracket, and , 27, n, plus, 103(9n+10) and 27n+10
3, left bracket, 9, n, right bracket, and , 27, n3(9n) and 27n
3, n, minus, 9, p, and , 9, p, minus, 3, n3n−9p and 9p−3n