Question

A student was asked to identify the variable in the expression 72x + 8. The student answered 72x. What was the student’s error?

Answer 1

The student did not divide x by 72 to isolate x completely.

After you have isolated a variable, if there is still a number attached to it, you must take the appropriate measures to remove it.

We'll use four examples here to display this.

x^2 = 100

for this, we must find the square root √ of both sides in order to isolate x.

x = 10

√x = 5

To find what x equals, we must square both sides to remove the √.

x = 25

5x = 10

To remove 5 from the variable, we must divide both sides by 5.

x = 2

x/5 = 4

To remove the /5 from x, we must multiply both sides by 5.

x = 20

Let me know if you have any questions!