Name: Timothy
Who is asking: Student
Level: Middle

Question:
My question is 3 = -2x

How do I isolate the variable here?



Hi Timothy,

The challenge is to manipulate the equation to end with one of the form x = ???, while maintaining the equality at each step. First I would rewrite the equation as

-2x = 3

You can multiply both sides of an equation by the same amount and maintain the equality, so at this point I would multiply both sides by -1. This will change the -2 to 2.

-1(-2x) = -1(3)
or
2x = -3

This equation is almost of the correct form x = ???, only the 2 remains as a problem. If you multiply both sides by  1/2 you will arrive at the desired form.

1/2(2 x) = 1/2(-3)
or
x = -3/2

Try another problem now. What about 5 = -3x?

Penny

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