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#1 2017-07-17 18:33:49

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Algebra

Q1. x=25(a^2) -25(b^2)  and Y=[5(a-b)]^2 then
A.  X=Y
B. X<Y
C. X>Y
D. None

Q2..  if a+b=3(c+d) which of the following is average of a,b,c,d
A. c+d
B.(c+d)\4
C. 3(c+d)\8
D. 3(c+d)\4

Q3.. if 7x+3y=17 and 3x+7y=19 , WHat is arithmetic mean of x and y???
A. 1.55
B. 1.8
C. 3.6
D. 36

Q.4  when a>b then (a^3)-(b^3) is greater than
A. zero
B..  (a+b)^3
C. (a-b)^3
D. none
Q5.. Rule to Add two scalar is Head to TAil rule or right hand rule or simple addition"??


MZk

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#2 2017-07-17 19:09:10

bob bundy
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Registered: 2010-06-20
Posts: 8,167

Re: Algebra

hi

Q1.  D is not a possible answer as one of the other  three must be true.

I tried this:


Now subtract:

If a = b then X = Y
If b>0 and b>a then 50b(b-a) > 0 then Y > X etc etc

So the answer seems to depend on the values of a and b.

Should answer D read "It is not possible to decide."

Q2.  Try simplifying (a+b+c+d)/4

Q3.  You could try solving for x and y, but a quicker method is to add the equations and re-arrange to find (x+y)/2

Q4.  I think this also depends on the values of a and b.  I need to spend more time on it so I'll come back to this question later.

LATER EDIT:

You can make a deduction from this if you know more about a and b such as a, b > 0 and b>a

Did you get told this at the start of these questions?  It's important to have the whole question.

Bob


Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#3 2017-07-17 21:06:04

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Re: Algebra

Plz decide only one option in question 1 I also know that option d is incorrect
Suppose if option d is
D. Not sure then ans d is correct

Last edited by Zeeshan 01 (2017-07-17 22:08:52)


MZk

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#4 2017-07-17 21:26:39

iamaditya
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From: Planet Mars
Registered: 2016-11-15
Posts: 743

Re: Algebra

You can also try one more formula for

It is


Practice makes a man perfect.
There is no substitute to hard work
All of us do not have equal talents but everybody has equal oppurtunities to build their talents.-APJ Abdul Kalam

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#5 2017-07-17 22:07:55

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Re: Algebra

Hehe I know all these formulas


MZk

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#6 2017-07-17 22:12:19

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Re: Algebra

bob wrote:

Q1.  D is not a possible answer as one of the other  three must be true.
I tried this:

Now subtract:

Why u subtract???


MZk

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#7 2017-07-18 00:20:48

bob bundy
Administrator
Registered: 2010-06-20
Posts: 8,167

Re: Algebra

A.  X=Y
B. X<Y
C. X>Y

If you calculate Y - X and the answer is:

zero ............. means Y = X

positive .........means Y > X

negative ........means X > Y

So subtracting was a quick way to help decide between the alternatives.

Bob


Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#8 2017-07-18 03:50:05

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Re: Algebra

??


MZk

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#9 2017-07-18 04:05:27

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Re: Algebra

Arithmetic mean formula is A=(x+y)\2


MZk

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#10 2017-07-19 00:17:59

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Re: Algebra

Can you Clearify Question 2,3,4???


MZk

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#11 2017-07-19 19:32:52

bob bundy
Administrator
Registered: 2010-06-20
Posts: 8,167

Re: Algebra

Q2. The average is (a + b + c + d)/4

If you start with this and use the given information to eliminate a and b it is a short work to get one of the possible answers.

Q3. Add the equations together : 10x + 10y = 36

It is a short step to get (x+y)/2

Q4.  Depending on what values I choose for a and b I get many possible answers:

If a=1.1 and b=1, then answers A and C are TRUE.

If a=-2 and b=-3, then answers A,B and C are all TRUE.

If a=1 and b=0, then answer A is TRUE.

I'll leave it to you to try to find a case where only D is TRUE.

Bob


Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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#12 2017-07-20 21:05:33

Zeeshan 01
Member
Registered: 2016-07-22
Posts: 648

Re: Algebra

Okk!,, it takes long time


MZk

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