Question

solving Special System

3x+y=4
-3x=y-7

Can you guys work it out so i can see how to do it.

Answer 1

from what i know i think its the substitution method so

make y the subject for the first equation:
3x+y=4
y=4-3x

then sub in 'y=4-3x' into the 2nd equation
-3x=y-7
-3x=(4-3x)-7

find x

then substitute in your x into the OTHER equation, not the one you derived it from, else you'll get something like 0=0

Answer 2

@donmath

Answer 3

@Green_Plan

Answer 4

@gudden

Answer 5

@undeadknight26

Answer 6

surd *eye twitches* i think this is an actual question...

Answer 7

yup

Answer 8

assuming you typed the equations correctly which i now doubt after attempting to solve ><

or maybe its not the substitution method after all oh well

Answer 9

@Auxuris how do you find x?

Answer 10

y= 7 - 3x equation one put in the other equation

Answer 11

well.

i don't think its solvable because the xs cancel out each other and i get:
0=-3 or something which certainly can't be right

let me try what donmath suggested, though if the first method didn't work, the other way round won't work as well.

Answer 12

nope i got '7=4' lmao

Answer 13

@surd .. ask a new question n then play the game.
this time let the question be " what was the name of first human being "

Answer 14

yes auxuris i also got 7=4

Answer 15

yup

Answer 16

omfg people am i missing something here

Answer 17

that was real funny gudden * laughing hard *

Answer 18

kk

Answer 19

@gudden

Answer 20

surd soldier get into your position

Answer 21

im entering enemys area

Answer 22

3x+y=4
-3x=y-7

I'd solve this by substitution. Since -3x=y-7, 3x=-(y-7).
Substituting the latter result into the first equation:

-(y-7) + y = 4
or
-y + 7 + y =4

7=4

this is never true, so this system has no solution.

Answer 23

Several of you respondents were on the right track.