K : Type u_1
inst✝¹ : Field K
inst✝ : NeZero 2
a b c x✝ : K
ha : a ≠ 0
h : discrim a b c = 0
x : K
this : discrim a b c = 0 * 0
⊢ a * x * x + b * x + c = 0 ↔ x = -b / (2 * a)
K : Type u_1
inst✝¹ : Field K
inst✝ : NeZero 2
a b c x✝ : K
ha : a ≠ 0
h : discrim a b c = 0
x : K
⊢ a * x * x + b * x + c = 0 ↔ x = -b / (2 * a)
have : discrim a b c = 0 * 0 := by rw [h, MulZeroClass.mul_zero]
no goals
K : Type u_1
inst✝¹ : Field K
inst✝ : NeZero 2
a b c x✝ : K
ha : a ≠ 0
h : discrim a b c = 0
x : K
this : discrim a b c = 0 * 0
⊢ a * x * x + b * x + c = 0 ↔ x = -b / (2 * a)
rw [quadratic_eq_zero_iff ha this, add_zero, sub_zero, or_self_iff]
no goals
K : Type u_1
inst✝¹ : Field K
inst✝ : NeZero 2
a b c x✝ : K
ha : a ≠ 0
h : discrim a b c = 0
x : K
⊢ discrim a b c = 0 * 0
rw [h, MulZeroClass.mul_zero]