7(x+3)=2x+51

[xeven_]

I am having trouble in math class. Can excel 2011 solve these types of equations? Can a calculator solve them?

 

[joeu2004]

I am having trouble in math class. Can excel 2011 solve these types of equations? Can a calculator solve them?

Excel does not solve equations directly. I believe there are calculators that do (TI 84?). But most don't.

Rather than have Excel produce a "magic number" for you, it would be better if you learned how to solve these type of equations for the unknown.

Uhm that means I may as well be reading chinese because that is exactly how I feel when I see all that.

I'm sure Rick is right: you are expected to use algebra to develop the solution yourself, without the use of calculators etc.

But all of us encounter math problems that we don't know how to solve ourselves. So let's look at how we might use Excel to help us with those problems.

An important concept to learn is: the equation 7(x+3) = 2x+51 can also be written
7(x+3) - (2x+51) = 0.

In other words, we just subtract the right side from the left side; the result should be zero.

So, in Excel, let's use cell B1 to represent "x". Then we set up the following formulas:

In A1: =7*(B1+3)
In A2: =2*B1+51
In A3: =A1-A2

Now use Goal Seek (or Solver) to find B1 such that A3 is zero.

Click on the Data tab at the top, then click on What-If Analysis, then Goal Seek. Fill in the following in the Goal Seek menu:

Set cell: A3
To value: 0
By changing cell: B1

Then click on OK. Voila! B1 is 6.

In this case, we can substitute 6 for "x" in the formulas and confirm that the integer works.

But for other problems, in might be necessary to change the cell format in order to see more decimal places. We need to choose a number of decimal places so that the formulas are approximately equal.

Also note that for other problems, the Goal Seek result might not be exactly right because Goal Seek stops iterating when predetermined conditions are met, just like you would give up after 100 or so iterations. In fact, sometimes even Goal Seek cannot find a solution.

Note: I believe Excel 2011 is a product for the Mac, and I am not familiar with it. The instructions above are for Excel 2010, which I presume is close.

 

[MikeLevine]

if you want an on-line solution finder for College Algebra, you can refer to: MathPapa

 

[tybaltlives]

I think what is needed here is for the OP to take a picture of the problem. Import the pic into excel and let Excel spit out the solution x=6.

Why can't Excel do this?

 

[Andrew Poulsom]

Do you realise that this thread is over a year old?

 

[Ingolf]

I think what is needed here is for the OP to take a picture of the problem. Import the pic into excel and let Excel spit out the solution x=6.

Why can't Excel do this?

Why you can not walk on the moon?

Because Excel is not designed for that.

 

[pgc01]

I think what is needed here is for the OP to take a picture of the problem. Import the pic into excel and let Excel spit out the solution x=6.

Why can't Excel do this?

That's a great idea.

If you have the time you could build an add-in that does that, in fact that gets a picture of any equation and solves it.

If you build it please share it.