Answer: The value of y is 3 units.
Step-by-step explanation:
Since we have given that
ABCD is a rectangle
So, their both diagonals are equal .
so, AC= BD
here,
[tex]AC=5y-2\\\\BD=4y+1[/tex]
So, According to question,
[tex]AC=BD\\\\5y-2=4y+1\\\\5y-4y=1+3\\\\y=3[/tex]
Hence, the value of y is 3 units.