Question

Solve the system of the linear equation and interpret your solution geometrically

2x+y+2z-4=0
x-y-z-2=0
x+2y-6z-12=o.

I have solved so many, am finding this one tricky, we use the elimination method to eliminate one of the variables..

Answer 1

no. 3 - no. 2 gives
-3y + 5z + 10 = 0
no. 1 - 2* no 2 gives
3y + 4z = 0

adding the above
9z = -10
z = -10/9

- can you continue with this (i'm tired!!!)

Answer 2

let me solve ill get back to you very soon.

Answer 3

ok - the -10/9 is correct - i checked it out on my calculator

Answer 4

check no3-no 2 u made a mistake with the sign

Answer 5

lol - sorry - although i put 3 - 2 - did 2 - 3 so it is correct

Answer 6

which should i do?

Answer 7

2 - 3 is ok

Answer 8

2-3 after which i will do 1-2 rty?

Answer 9

now you you could plug z = -10/9
into equations 1 and 2
and solve for x and y

Answer 10

cwrw238 has correct value for z. This problem does not have pretty answers. But you are on track with cwrw238.

Answer 11

did you say 1-2? for the second one

Answer 12

thanks radar?

Answer 13

am confused????

Answer 14

i did 2-3 i got -3y+5z+10=0
what should i do next???

Answer 15

no i multiplied no 2 by 2 because no 1 has 2x in it
so no 2 becomes

2x - 2y - 2z - 4 = 0

im afraid i didn't show this step

then no 1 - this equation gave
3y + 4z = 0

Answer 16

-3y+5z+10=0 is correct
now add 3y + 4z = 0 (derived above)
to get
an equation in z

Answer 17

good i now have the two equations so i should add them up right?

Answer 18

yes add them

Answer 19

yeah z= -10/9

Answer 20

right now you can plug z into, i suggest, no 1 and no 2 equations to give 2 equations in x and y

Answer 21

for the first one 2x+y-56/9=0

Answer 22

and for the second one x-y-8/9=0

Answer 23

yes

Answer 24

yeah so whats next?

Answer 25

well solve these 2 equations by elimination
adding them will eliminate y ( as they contain y and -y)