Confusion about assignment axiom in Hoare logic

Question

I wanted to know if we are given the f.f.g. Hoare triple:

{x = 43}x := x + 1{x = 44}

How do we show that this is a valid Hoare triple?

My attempt was:

Using the assignment axiom: {x + 1 = 43} x := x + 1 {x = 44}

But this doesn'the make sense. I also want to know what went wrong in my attempt?