no goals
R : Type u_1
A : Type u_2
inst✝² : Semiring R
inst✝¹ : NonUnitalNonAssocSemiring A
inst✝ : DistribMulAction R A
r : R
a : A
⊢ r • a + 0 • 0 + 0 * a = r • a
rw [smul_zero, add_zero, MulZeroClass.zero_mul, add_zero]