Answer:
y = -¹/₂ x - 6
Explanation:
Two lines are perpendicular if the product of theirs slopes is equal -1:
y=m₁x+b₁ ⊥ y=m₂x+b₂ ⇒ m₁×m₂ = -1
y = 2x + 3 ⇒ m₁=2
2×m₂ = -1 ⇒ m₂ = -¹/₂
The y-intercept is b=-6 so the equation in slope-intercept form:
y = -¹/₂ x - 6