Solve xy-5=k for x.

Question

Solve xy-5=k for x.

anonymous · Answer

See I am not sure if I should add the 5 first to both sides or divide the y first to both sides

e.mccormick · Answer

If you divide first, you end up with $-\frac{5}{k}$ on one side and a fraction on the other too....

e.mccormick · Answer

When doing "solve for..." type things, take the order of operations and reverse it.  So PEMDAS becomes SADMEP... basically.  Or ASMDEP....  The addition and Subtraction still happen at the same time, as do Multiplication and Division.

anonymous · Answer

So I should add first

e.mccormick · Answer

Yah.

e.mccormick · Answer

The great thing is, if you know your order of operations, then you know this rule too!  It is just in the mirror and reversed.

Every part of math has this.  The un-do equation.  So to undo addition you separate things.  To undo multiplication you factor.  Well, the undoing of order of operations is solve for this or that.