I am having difficulty with this equation. I have been working with it for several weeks! Please Help.

the equation is this:
solve for Lf
Lf=[(CwMw+CsMs+CcMc)(To-Tf)//Mi-CwTf

values
Cw=1.00; Mw=143.4; Cs=0.11; Ms=30.0; Cc=0.22; Mc=57.7;To=23.9; Tf=14.2;Mi=16.7

I keep comming up with something in the neighborhood of 618.5 cal/g
the computer program we ran during this experiment has Lf=78.4 cal/g
Lf needs to equal as close to 80 cal/g and I need to be with in 10% 80 cal/g. Can anyone help me.

Here is what I've been doing what am I doing wrong?
Lf=[(1.00*143.4+0.11*30.0+0.22*57.7)=143.4+3.3+12.69/(15.7)(14.2)
=159.39*9.7/15.7*14.2
=1546.08/222.94
=6.93

Lf=[(CwMw+CsMs+CcMc)(To-Tf)//Mi-CwTf

values
Cw=1.00; Mw=143.4; Cs=0.11; Ms=30.0; Cc=0.22; Mc=57.7;To=23.9; Tf=14.2;Mi=16.7

The closing parenthesis ] is missing.

What does // mean after (To - Tf)? Is the first /supposed to be a ]?

Until these items are corrected, an answer is not obtainable.

Removing the first [ and one of the / yields 572.63.

Other possibilities are

Lf=[(CwMw+CsMs+CcMc)(To-Tf)]/Mi - CwTf

Lf=[(CwMw+CsMs+CcMc)(To-Tf)]/(Mi - CwTf)

Lf=[(CwMw+CsMs+CcMc)(To-Tf)/Mi] - CwTf

To solve the equation Lf = [(CwMw + CsMs + CcMc)(To - Tf)] / (Mi - CwTf) for Lf, we'll substitute the given values into the equation and simplify step by step.

Given values:
Cw = 1.00
Mw = 143.4
Cs = 0.11
Ms = 30.0
Cc = 0.22
Mc = 57.7
To = 23.9
Tf = 14.2
Mi = 16.7

Step 1: Substitute the given values into the equation:
Lf = [(1.00 * 143.4 + 0.11 * 30.0 + 0.22 * 57.7)(23.9 - 14.2)] / (16.7 - 1.00 * 14.2)

Step 2: Simplify the expression inside the brackets:
Lf = [(143.4 + 3.3 + 12.694)(9.7)] / (16.7 - 14.2)

Step 3: Continue simplifying:
Lf = [(159.394)(9.7)] / (2.5)

Step 4: Evaluate the numerator:
Lf = 1546.0738 / 2.5

Step 5: Divide to find the final answer:
Lf = 618.42952 cal/g

Based on your calculations, you're obtaining Lf = 618.5 cal/g, which is close to the computer program's value of Lf = 78.4 cal/g. However, the desired result is Lf = 80 cal/g with a tolerance of 10%.

To check what might have gone wrong, let's analyze your calculation:
Lf = [(1.00 * 143.4 + 0.11 * 30.0 + 0.22 * 57.7)(23.9 - 14.2)] / (16.7 - 1.00 * 14.2)
Lf = [(143.4 + 3.3 + 12.69)(9.7)] / (2.5)
Lf = [159.39 * 9.7] / 2.5
Lf = 1546.08 / 2.5
Lf = 618.432 cal/g (rounding to three decimal places)

It seems that you made a rounding error in the final step. Instead of rounding to one decimal place, make sure to round to three decimal places, as required. So, your calculation is almost accurate.

The result obtained by the computer program, Lf = 78.4 cal/g, is significantly different from your result. It might be worth double-checking if the equation you're using is correct or if any data values were inputted incorrectly.

Considering the desired value of Lf = 80 cal/g with a tolerance of 10%, we can see that your calculated Lf of 618.432 cal/g is far beyond that range. Therefore, it is important to re-evaluate the equation and ensure the accuracy of the values being used.