The last one is the answer
X = 5 or x = 13.
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I just tried to help someone with the same problems. I hope this helps you
Answer:
A variable is a quantity that may change within the context of a mathematical problem or experiment. Typically, we use a single letter to represent a variable. The letters x, y, and z are common generic symbols used for variables.
Step-by-step explanation:
in other words is like x,y,z or any other letters
