SOLUTION: What is n for this formula please. (4n-6)x1/2=5 and (5n-3)x2/4-1=5, it says to backtrack to solve n, help would be much appreciated. Thankyou Maria

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: What is n for this formula please. (4n-6)x1/2=5 and (5n-3)x2/4-1=5, it says to backtrack to solve n, help would be much appreciated. Thankyou Maria      Log On


   



Question 872597: What is n for this formula please. (4n-6)x1/2=5 and (5n-3)x2/4-1=5, it says to backtrack to solve n, help would be much appreciated. Thankyou Maria
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
(4n-6)×1%2F2=5

Let's go forward first with n and then we'll know how to backtrack

Start by pretending that you know what number the letter n represents.

1.  Start with n
2.  Multiply n by 4        --->  you get 4n
3.  Subtract 6             --->  Now you have (4n-6)
4.  Multiply by 1%2F2         --->  Now you have (4n-6)×1%2F2 and you 
                                 have finished and you knoe that the answer
                                 you got here would have equaled to 5

Now let's backtrack:

Start with 5, for that's what the answer was. 
We take 5 and do the opposite of what we did in step 4.
Step 4 was to multiply by 1%2F2 
The opposite of multiply is divide,
So we divide 5 by 1%2F21%2F2 = 5%2F1÷1%2F2 = 5%2F1×2%2F1 = 10%2F1 = 10

So backtracking on step 4 gives us 10

We take 10 and do the opposite of what we did in step 3.
Step 3 was to subtract 6 
The opposite of subtract is add,
So we add 6 to 10

10+6 = 16

So backtracking on step 3 gives us 16

We take 16 and do the opposite of what we did in step 2.
Step 2 was to multiply by 4 
The opposite of multiply is divide.
So we divide 16 by 4

16÷4 = 4

So backtracking on step 4 gives us 4

Since step 1 was "Start with n", we have ended with n

Therefore the letter n equals 4, or n=4.

That is the solution n=4

-------------

Let's check n=4 to make sure it is correct:

(4n-6)×1%2F2 =5   <--- put ×4 for n
(4×4-6)×1%2F2 =5  <--- multiply 4 by 4, get 16 
(16-6)×1%2F2 =5   <--- subtract 16-6, get 10
(10)×1%2F2 =5     <--- multiply 10 by 1%2F2, get 5
5 = 5          <--- both sides of the = have the same number 5

So n=4 is the correct solution.

See if you can backtrack on the other one the same way.

If you have trouble, just tell me in the thank-you note and I'll
get back to you.

Edwin