+0

# Plz help me on this

-2
78
5

Find the ordered triple, (p,q,r)

\begin{align*} p-2q&=0\\ q-2r&=0\\ p+r&=5. \end{align*}

Jul 2, 2020

#1
+1

Add equations: (p - 2q) + (q - 2r) + (p + r) = 0 + 0 + 5 ==> 2p - q - r = 5

Divide first equation by 2: p/2 - q = 0

Subtract equations: 5p/2 - r = 0 == > r = 5p/2

Substitute into third equation: p + 5p/2 = 5 ==> 7p/2 = 5 ==> p = 10/7

First equation: p - 2q = 0 ==> q = p/2 = 5/7

Second equation: q - 2r = 0 ==> r = q/2 = 5/14

Solution: (10/7, 5/7, 5/14)

Jul 2, 2020
#2
-4

hmmm it appears to be wrong

Creampuff  Jul 2, 2020
#3
+1

p - 2q  =  0     --->                       p - 2q       =  0

q - 2r  =  0     --->   x 2   --->            2q - 4r  =  0

Add down:                                 p         - 4r  =  0

p - 4r  =  0     --->                      p - 4r  =  0

p + r  =  5     --->   x -1   --->    -p  -  r  =  -5

Add down:                                   - 5r  =  -5

r  =  1

p + r  =  5   --->   p + 1  =  5     --->     p  =  4

q - 2r  =  0   --->   q - 2(1)  =  0     --->   q  =  2

Jul 2, 2020
#5
+2

we first find that q=2r and substitute p-2q into p-4r where we add p+r to get 2p-3r=5  and we also get that p=2q so p=4r and we get 8r-3r=5 so r=1 and then q=2 and p=4 so the ordered pair is (4,2,1).

Jul 2, 2020