Answer:
y= 8 and the diagonal = 32
Explanation:
In a rectangle, both diagonals are equivalent. Using this information we set up the diagonal equations of AC and BD to each other, and then solve for y.
5y+12=7y+4
We have to isolate the variable, so we get the like terms on one side.
8=2y
8÷2=4
y=4
knowing that y =4 helps with each diagonal.
5(4)+12
20+12=32
7(4)+4
28+4=32