Question

Please help me with this system. I'm not getting the y or z.

-x+2y+z=2
3x+y+z=12
x-y-2z=-1

Answer 1

(3,2,1)

Answer 2

Can u explain it to me please?

Answer 3

are you supposed to use elimation?

Answer 4

Either elimination or substitution

Answer 5

ok we can eleminate z first

Answer 6

satellite, i wasnt done, i still needed helpp :/

Answer 7

\[-x+2y+z=2\]
\[ 3x+y+z=12\]

Answer 8

subtract and get
\[-4x+y=-10\] as one equation with no z in it

Answer 9

now
\[3x+y+z=12\]
\[ x-y-2z=-1\]
multiply first equation by 2 get
\[6x+2y+2z=24\]
\[x-y-2z=-1\] add and get
\[7x+y=23\]

Answer 10

now we have
\[-4x+y=-10\] and
\[7x+y=23\] so solve

Answer 11

subtact second one from first and get
\[-11x=-33\] making
\[x=3\] now substitute back to find y, and then z

Answer 12

Where did the y go in the -4x+y=-10
and 7x+y=23

Answer 13

i subtracted the second equation from the first

Answer 14

oh you multiplied by -1

Answer 15

or if you prefer, multiply the second by -1 and then add,

Answer 16

yes exactly
it is the same thing

Answer 17

ok I got it finally
thank you so much for your help

Answer 18

\[-4x+y=-10\]
\[-7x-y=-23\]
\[-11x=-33\] etc
yw