Question

solve by substitution
please help me im not sure how to do this

Answer 1

-x-y-z=-8
-4x+4y+5z=7
2x+2z=4

Answer 2

call : x - 4y + z = 6 (e1) == > z = 6 - x + 4y
2x + 5y - z = 7 (e2)
2x - y - z = 1 (e3)

sub z from e1 in e2 you have :
2x + 5y - 6 + x - 4y = 7 ==> 3x + y = 13 ==> 3x = 13 - y (*)
sub z from e1 in e3 you have:
2x - y - 6 + x - 4y = 1 ==> 3x - 5y = 7 (**)

sub 3x from (*) in (**), you have
13 - y - 5y = 7 ==> 6 = 6y ==> y = 1
sub y = 1 into (*), you have:
3x = 13 - 1 = 12 ==> x = 4

sub both y = 1 and x = 4 into (e1), you have:
4 - 4(1) + z = 6 ==> z = 6

so answer : x = 4, y = 1, z =6 (you can use these values to check other equations to see if they come out all right)

Answer 3

make sense or no?

Answer 4

can you do this like step by step so i understand more please @taylor0402

Answer 5

its kind of hard for me to explain anyother way sorrn :((

Answer 6

-x-y-z=-8
x+y+z=8
x+z=8-y
2x+2z=16-2y
16-2y=4
2y=16-4=12
y=12/2=6
-4x+4y+5z=7
-4x+4*6+5z=7
-4x+5z=7-24=-17 ...(1)

2x+2z=4
x+z=2 ... (2)
x=2-z
put in (1)
-4(2-z)+5z=-17
-8+4z+5z=-17
9z=-17+8=-9
z=-9/9=-1
put in (2)
x-1=2
x=2+1=3
x=3,y=6,z=-1