Welcome to Test-paper.info
Saturday, June 24 2017 @ 12:22 PM CDT
 Select a Forum » General Chat » Primary 1 Matters » Primary 2 Matters » Primary 3 Matters » Primary 4 Matters » Primary 5 Matters » Primary 6 Matters » Question, Feedback and Comments » Education Classified
 Forum Index >  Test Paper Related >  Primary 6 Matters Math
 | Printable Version
 By: soonteck_01 (offline)  Sunday, February 09 2014 @ 01:18 AM CST (Read 716 times)
soonteck_01

Q1. x+y/3=x-y/5=2x-3y+5
Solve for x and y

Q2. If x=3 and y=-1 is the solution of the simultaneous equations

3px+qy=11
-qx+5y=p
find the value of p and q

Newbie

Registered: 07/31/13
Posts: 5

 By: echeewh (offline)  Sunday, February 09 2014 @ 09:54 PM CST
echeewh

Hey <soonteck_01>

This is not Primary maths that you are asking. And I'm afraid you are putting your questions in the wrong category as always.

Anyway following are my worked solutions ....

Q1

Form 2 equations with x,y in it and apply the Simultaneous method to solve it (since there are only 2 variables x and y)

x+y/3=x-y/5
5(x+y) = 3(x-y)
5x + 5y = 3x - 3y
5x + 5y - 3x + 3y = 0
2x + 8y = 0 -- (1)

x-y/5=2x-3y+5
x - y = 5(2x-3y+5)
x - y = 10x - 15y + 25
x - y - 10x + 15y = 25
14y - 9x = 25 -- (2)

Eliminating x, multiply (1) 9x, (2) 2x as follows:

(1)x9:
18x + 72y = 0 -- (3)

(2)x2:
28y - 18x = 50 -- (4)

Comparing (3),(4)
(3)+(4):
72y + 28y = 50
100y = 50
y = 5/10 = 1/2

Sub y into (1), we have ...
2x + 8(1/2) = 0
2x + 4 = 0
2x = -4
x = -(4/2) = - 2

=========

Q2.

9p - q = 11 -- (1)
-3q - 5 = p
-p - 3q = 5 -- (2)

(1)x3:
27p - 3q = 33 -- (3)

(3)-(2):
27p + p = 33 - 5
28p = 28
p = 1

in (1), we have ...
9(1) - q = 11
q = 9 - 11 = - 2

==========

Trust the above helps.

Do let me know again if this is different from your <Answerkey> or if there's further clarification.

Cheers,
Edward

Active Member

Registered: 04/21/11
Posts: 623

 All times are CDT. The time is now 12:22 pm.
 Normal Topic Locked Topic Sticky Topic
 New Post Sticky Topic w/ New Post Locked Topic w/ New Post
 View Anonymous Posts Able to Post HTML Allowed Censored Content