(a + 3*d)*(a + d + 2)
1*(a + 3*d)*(a + 2 + d)
(1*(a + 3*d))*(a + (2 + d))
2 2 a + 2*a + 3*d + 6*d + 4*a*d
a^2 + 2*a + 3*d^2 + 6*d + 4*a*d
(a + 3.0*d)*(2.0 + a + d)