Update lambda-calculus-bonus-exercises-answers.md

[skilgal]

Fix the typo on task 4

[k-bx]

There is indeed an error, but not where you've fixed it :) Here's the correct fix:

[skilgal]

Actually I can't see the difference.

My substitution is [y -> y1] and your's [y -> w] .
but the other part looks the same.
There is some difference in the braces, but according to the CR..smth that it shouldn't make the difference.

λw1. (λz. (λc. y)z)w <=> λy1. ((λz. (λc. y)z)y1)

for me, it looks like
λx. x y <=> λx. (x y)

Correct me if I'm wrong

[skilgal]

Okay, maybe found what you meant.
The lambda transformation should be done as first since on my second line we get a collision

[k-bx]

I would explicitly add alpha-renaming as a step before doing the beta-reduction, but this looks correct now.