Answer:
x=lengthNEW-lengthOLD
Explanation:
The length of the tree used to be only 1.85m. We call this the old length value of the tree, or in short: "lengthOLD"
Next the tree grew to be 5.30m. We call this the new length value of the tree because this measurement was taken later in time, and so after the first measurment. In short: "lengthNEW" is always the newwest value.
To calculate how much the tree has grown, you need to subtract the two lengths. It alway goes in this way:
The newwest number minus the old number.
In this case: x=lengthNEW-lengthOLD