A. square
explanation: a square has four equal side lengths and four right angles, the other shapes do not fit the criteria
Step-by-step explanation:
12a = 13a - a
12a = 14a - 2a
12a = 15a - 3a
12a = 16a - 4a
12a = 17a - 5a
...
There is no upper limit so, so x is greater than or equal to 24 (x ≥ 24)
The value of x is
-4x + 8 = 42
-4x = 42 -8
-4x = 34
x = -8,5