Final answer:
In a parallelogram, the sum of the opposite angles is always 180 degrees.
Step-by-step explanation:
The given information describes a parallelogram with angles R, RQS, SQT, and T. We can use the relationships between the angles in a parallelogram to determine which equation is not true. The sum of the opposite angles in a parallelogram is always 180 degrees. Therefore, the equation (15x + 55) + (4x) = (6x) + (26x) is not true.