The first thing we want to do is isolate t², rather than t. Why? As you can see when we substitute t² into the second equation, it will be easier than substituting t, as t is present in the form t². So, let's isolate t² in the first equation --- ( 1 )
x = t² + 2,
t² = x - 2
Now let's substitute this value of t² in the second equation --- ( 2 )