Solve for h

[samwertz3]

S=2B+Ph is an example of the problem that I am working on.

I am supposed to solve for h.

Do I solve such equations like h=S-2B/P or h=S/P-2B

If I follow the order of operations the solution would be the second, but I have been getting these wrong in my class so any suggestions would be great.

Thanks.

 

[Mrspi]

S=2B+Ph is an example of the problem that I am working on.

I am supposed to solve for h.

Do I solve such equations like h=S-2B/P or h=S/P-2B

If I follow the order of operations the solution would be the second, but I have been getting these wrong in my class so any suggestions would be great.

Thanks.

If you're solving for "h", get all terms containing "h" on one side of the equals sign, and all terms that DO NOT contain h on the other side.

You've got only one term containing "h" in

S = 2B + Ph

To get the term containing "h" by itself on one side of the equals sign, SUBTRACT 2B from both sides of the equation:

S - 2B = 2B + Ph - 2B

Combine like terms:

S - 2B = Ph

Now...do you see that "h" has been multiplied by P? To "undo" that multiplication, divide both sides of the equation by P:

(S - 2B) / P = (Ph)/P

(S - 2B) / P = h

If you follow the order of operations, you do NOT get the second answer choice indicated in your original question.

 

[samwertz3]

Ok thanks for the help. I guess I was confused because I thought in the order of operations division came before addition or subtraction. So that is why I was dividing the p out first. But I get it now, thanks again.

 

[mmm4444bot]

… I thought in the order of operations division came before addition or subtraction …

It does -- when you're evaluating an expression.

43/2.5 + 16 = ?

Here, we're evaluating the expression on the lefthand side, so we divide by 2.5 before adding 16.

When we're solving an equation for one of its symbols, then -- as Mrs. Pi noted -- we're actually "undoing" the order of operations, and that's why we sort of work in reverse.

 

[samwertz3]

Re:

… I thought in the order of operations division came before addition or subtraction …

It does -- when you're evaluating an expression.

43/2.5 + 16 = ?

Here, we're evaluating the expression on the lefthand side, so we divide by 2.5 before adding 16.

When we're solving an equation for one of its symbols, then -- as Mrs. Pi noted -- we're actually "undoing" the order of operations, and that's why we sort of work in reverse.

Ok, I got it now. Your explanation makes the process clearer. Thanks.

 

[Deleted member 4993]

S=2B+Ph is an example of the problem that I am working on.

I am supposed to solve for h.

Do I solve such equations like h=S-2B/P or h=S/P-2B

If I follow the order of operations the solution would be the second, but I have been getting these wrong in my class so any suggestions would be great.

Thanks.

You could do the otherway - however you'll have to be careful:

S=2B+Ph

S/P = 2B/P + h........................Divided by 'P' - both sides to isolate 'h'

S/P - 2B/P = h ........................Subtracted for further isolation

h = (S-2B)/P ...........................Combined - not a necessary step