Question

Let a Δ b = (a+b)2+5. what is 1 Δ - 4?

Answer 1

It looks like ∆ is defined as

a ∆ b = (a + b)² + 5

If that's the case, then

1 ∆ (-4) = (1 + (-4))² + 5 = (-3)² + 5 = 9 + 5 = 14