help solving this system?

Question

x +3y +5z = 20
y - 4z= -16
3x - 2y +9z = 36

Answer 1

x +3y +5z = 20
3x - 2y +9z = 36

multiply a) by -3 and add gives
-11y-6z=-24

combine with by multiplying with 11 and adding them
y-4z=-16

gives
-50z = -24 -16*-11

so z = - 3.04
fill that value into y-4z = -16 will give you y
and with y and z into the first equation will give you x.

Answer 2

i got a sol for u frnd
(x+3y+5z=20) - (y-4z=-16)*3 GIVES (x+17z=68)say equ1
(3x-2y+9z=36)+(y-4z=-16)*2 GIVES (3x+z=4)say equ2

equ1-17*equ2 GIVES x=0
now substiute x=0 in x+3y+5z=20
we get (3y+5z=20) say equ3
equ3*4+(y-4z=-16)*5 gives y=0
now substitute y=0in any of the equ we get z=4

sweetdreams

Answer 3

the first three numbers into a matrix on your calculator
substitute 0's in where there isn't an x
so the matrix would look like this
1 3 5
0 1 -4
3 -2 9

and make another matrix with the constant values in it
20
-16
36

then do matrix a^-1 times matrix b

Answer 4

if you take terms across the equals sign,
e.g. y -4z = -16 becomes y = 4z -16, then you can substitute this into the other expressions, until you have an expression with just one variable, then you can substitute that value into the other expressions to find the values of all the variables.

Answer 5

either solve for a single variable in an equation and substitute it in to a different equation or use linear combination
or u could solve by turning the system into a matrix I wont give details because I'm lazy but you can look these strategies up using ask.com

Answer 6

Multiply the 1st equation by -3 and add result to 3rd equqtion.
This will give you a new equation with x eliminated.
Use it with the 2nd equation to solve for y and z.
Then you can find x

Answer 7

-2

Answer 8

yea u need to pay attention when the teacher is explaning it in class or go for help during launch.
do ur work ur self