Answer:
The value of x is 4.
Explanation:
Consider a Rectangle ABCD
AB as Top
CD as Bottom
AB = -1 + 4x
CD = 3x + 3
To Find:
x = ?
Solution:
In a Rectangle ABCD
Opposite sides of Rectangle congruent,......Property of Rectangle
AB = CD
Top = Bottom
On substituting we get

Therefore the value of x is 4.