Answer:
x = 7
Step-by-step explanation:
Assuming the quadrilateral is a parallelogram, then the diagonals bisect each other.
7x - 8 = 41
7x = 49
x = 7
Answer:
It appears to be substitution
Step-by-step explanation:
I think you are talking about system of equations

This is because 
And 
For this reason, 
Positive indices mean we have to multiply the same number twice or thrice based on the value of the index. On the other hand, negative indices mean we have to divide by the same number twice or thrice based on the value of the index.