High School Math Problem

[AreaCode707]

I'm trying to be a hero to my 15 year old sister (I'm 27) and help her learn her algebra in solving a system of three equations but I'm an English retard. Anyone up for explaining the logic behind this problem so I can help explain it to her?

p+4r=-7
p-3q=-8
q+r=1

 

[JMapleton]

Troll post. The only responses you'll get are people asking for pics, you know this, but post it anyway.

 

[lozina]

damn you and you sister are 12 years apart? what happened there?

 

[coldmeat]

Treat it as a matrix and put it in reduced row echelon form. Duh so simple.

 

[AreaCode707]

damn you and you sister are 12 years apart? what happened there?

Surprise blessing. Twins.

 

[PieIsAwesome]

p = -7 - 4r
p = -8 +3q

=> 3q + 4r = 1 => 3q = 1 - 4r

3(q + r = 1) => 3q + 3r = 3 => 3q = 3-3r

=>1-4r = 3-3r
-2 = r

plug into another equation, get new variable, plug into another, etc.

There is the matrix method but I never do it unless I am using a calculator so I forgot.

 

[AreaCode707]

Troll post. The only responses you'll get are people asking for pics, you know this, but post it anyway.

Troll post would require me to be intentionally trying to stir up the forum, which is entirely not the case. Other people's bad behavior in asking for pedo pics is NOT my problem.

 

[AreaCode707]

p = -7 - 4r
p = -8 +3q

=> 3q + 4r = 1 => 3q = 1 - 4r

3(q + r = 1) => 3q + 3r = 3 => 3q = 3-3r

=>1-4r = 3-3r
-2 = r

plug into another equation, get new variable, plug into another, etc.

There is the matrix method but I never do it unless I am using a calculator so I forgot.

You rock! We're still working through what you did but this got us started down the right track. Thank you!!!

[edit] Yeah!! We worked through the logic and she understands the idea now. Thank you soo so much!

 

[RPD]

3 equations, 3 unknowns...

 

[bommy261]

derp derp?

 

[OCGuy]

:camera;?

 

[silverpig]

i'm trying to be a hero to my 15 year old sister (i'm 27) and help her learn her algebra in solving a system of three equations but i'm an english retard. anyone up for explaining the logic behind this problem so i can help explain it to her?

P+4r=-7
p-3q=-8
q+r=1

1  0  4 | -7
1 -3  0 | -8
0  1  1 |  1

1  0  4 | -7
0 -3 -4 | -1
0  1  1 |  1

1  0  4 | -7
0  0 -1 |  2
0  1  1 |  1

1  0  4 | -7
0  0  1 | -2
0  1  1 |  1

1  0  4 | -7
0  0  1 | -2
0  1  0 |  3

1  0  0 |  1
0  0  1 | -2
0  1  0 |  3

1  0  0 |  1
0  1  0 |  3
0  0  1 | -2

p =  1
q =  3
r = -2

I hope I did that right.