All Answers 358090 Answers

0.970025 m^2 / 28 m^2 = 0.03464375.

1.205 m*0.805 m = 0.970025 m^2.

Thanks, Alan, for that answer.....!!!

For the last 2 expansions there is an invisable -1 between the minus sign and the bracket. 

So when you expand the bracket all the minuses become Plus and the pluses  become minuses.

ex.    -(x+3-y)=-1(x+3-y) = -x-3+y

You are welcome. 

thanks @melody

I would do it CPhill's way but I would use a venn disagram to help me.

I have just started it here.   

If you want to know how to do this on the site calc then look at this thread.

Ok then, I will  answer the question that you have asked.  

$$\begin{array}{rll}
\frac{1}{2}(6-z)&=&z\\
\frac{1}{2}(6-z)\times 2&=&z \times 2\\
6-z&=&2z\\
6-z+z&=&2z+z\\
6&=&3z\\
\frac{6}{3}&=&\frac{3z}{3}\\
2&=&z\\
z&=&2\\
\end{array}$$

its exactky as the way its shown its just that im working with equations that have variables and thats the way it was shown to me 

the answer is 1.4

Does the (6-z) belong on the top as indicated by pedmas OR does it belong on the bottom?  Either way it would be good if you used more brackets to make your meaning clear.  Thanks. 

Thanks CPhill for taking the time out to try to help. Thanks for the link as well, i'll check it out.

Alan: You came through for me again mate! I didn't know if it was possible to do it through the SC but i had a hunch it was but just didn't have a clue what to do or how to go about it!

You've helped me so much with that answer.

The book we talked about before 'Electronics: A Systems Approach' page 62. The coefficient matrix on the left there is the one i'm talking about calculating. From the Algebra book i'm studying it says get the inverse matrix and then multiply it with the constants matrix to get the solution to the systems of equations problem but using a matrix instead of doing it by hand.

Thanks Alan you're a great help. 

 Gary

You need to supply the values for Cp1, Cp2, t1 and t2.

You can do it on the calculator here.  First select vectors/matrices from the right side of the input bar. Then choose 3x3 matrix for A and B.  Enter your coefficients in A.  keep zeros in B. Select ^-1 for A and + for combining the matrices, then press =.  A little cumbersome, but it works!

4 play neither

x play volleball only

9x play both tennis and volleyball

And (30 -9x) play tennis only

So we have

4 + x + 9x + (30 - 9x) = 36

34 + x = 36

x = 2 = those who play volleyball only

So 9(2) = 18 play tennis and volleyball

And (30 - 9(2))  = (30 -18) = 12 play tennis only

And

4 + 2 + 18 + 12 = 36

Two examples may help more than a detailed explanation.

Suppose we have .000003567

Move the decimal one place to the right of the first non-zero digit and write:

3.567 x 10^-6    where "6" is the number of places we moved the decimal to the right

Now suppose we have 3567

Again, move the decimal one place to the right of the first non-zero digit and write:

3.567 x 10³      where "3" is the number of places we moved the decimal to the left

So....moving the decimal to the right results in a negative exponent on 10. And moving it to the left results in a positive exponent on 10.

Hope that helps.

I don't think the calculator on this site has the capability to do this, and I'm not sure what type of calculator you're using, so I can't tell you how to do this......(maybe look at your manual???)

However, here's a pretty good website, WolframA;pha, that will calculate an inverse of an invertible square matrix........

http://www.wolframalpha.com/input/?i=inverse+matrix&a=*C.inverse+matrix-_*Calculator.dflt-&f2={{5%2C4%2C9}%2C{3%2C2%2C1}%2C{2%2C1%2C3}}&f=MatrixInverse.invmatrix_{{5%2C4%2C9}%2C{3%2C2%2C1}%2C{2%2C1%2C3}}

I don't know if that helps you, or not.

You can start by assuming that, if it factors nicely, it will be in the form

(ax + b)(cx + d) where a, b, c and d are nice whole numbers (positive or negative).

Expanding these brackets we get:

(ax + b)(cx + d)  =  a*c*x² + a*d*x + b*c*x + b*d = a*c*x² + (a*d + b*c)*x + b*d 

Now compare this with the left-hand side of your equation 6x² - 5x - 4

A. From the constant term we must have b*d = -4, so the magnitudes of b and d must be 1 and 4 or 2 and 2.

B. From the x²  term a*c = 6 so the magnitudes of a and c must be 1 and 6 or 2 and 3

C. From the x term we must have a*d + b*c = -5

Now you have to try various combinations of a, b, c and d from A and B until you get C correctly (you'll have to include the possiblity that the signs are positive or negative as well).  This sounds like a lot of combinations, but actually there aren't that many to try and you'll find the right values fairly quickly.

If no combinations fit it means the equation doesn't factorize nicely and you would have to use the quadratic formula.

Alternatively, you could use the quadratic formula right away!