Math problems..................

[BustaBust]

How do you do this:

20. For the following set of scores, find the value of each expression:

X
------
5
-2
0
3
a. SX
b. SX2
c. S(X + 3)


24. For the following set of scores, find the value of each expression:

X
-------
9
1
1
1
a. SX2
b. (SX)2
c. S(X ? 3)
d. S(X ? 3)2

It is fairly easy, but I've been away from Math so long that I am not confident in my answer.

 

[nycxandy]

So what are your answers?

 

[BustaBust]

20b is supposed to be squared, as is 24a,b, and d.

20a= 6?

 

[dullard]

SX = x1+x2+x3+...

Thus SX = 5 + -2 + 0 + 3 = 6

The rest are the same technique.

 

[Gunslinger08]

6
38
18

84
144
0
48

 

[DrPizza]

The S symbol means summation

(S for summation, except in Greek)

 

[BustaBust]

I got these: (Correct me if I am wrong)

20
A. 6
B. 36
C. 9

24
A. 144
B. 144
C. 9
D. 81

Remember 20b, 24a, 24b, and 24d are supposed to be squared not "2"

 

[BustaBust]

Correct?

 

[shilala]

I got four and a half.

 

[BustaBust]

Shilala........what are you talking about?

 

[Gunslinger08]

Originally posted by: BustaBust
I got these: (Correct me if I am wrong)

20
A. 6
B. 36
C. 9

24
A. 144
B. 144
C. 9
D. 81

Remember 20b, 24a, 24b, and 24d are supposed to be squared not "2"

Incorrect.
Check your answers.
Mine are correct.

 

[dullard]

Originally posted by: BustaBust
I got these: (Correct me if I am wrong)

The issue is the order of operations. The parenthesis is most important. Do whatever is inside them first, then do the rest. Squaring is more important than adding, so square before you add. Thus:

SX = x1 + x2 + x3 + x4

SX^2 = x1^2 + x2^2 + x3^2 + x4^2

S(X + 3) = (x1+3) + (x2+3) + (x3+3) + (x4+3)

(SX)^2 = (x1 + x2 + x3 + x4) ^ 2

S(X - 3) = (x1-3) + (x2-3) + (x3-3) + (x4-3)

S(X ? 3)^2 = (x1-3)^2 + (x2-3)^2 + (x3-3)^2 + (x4-3)^2

I did the math quickly in my head and joshsquall appeard to get them correct.

Sorry I put the sum in, but when I edited the post, the sums left, pretend the 'S' is the summation sign.