Question

Solve The System By Elimination. -2x+2y+3z=0 (Rest Is In Comments)

Answer 1

-2x + 2y + 3z = 0
-2x - y + z = -3 --->(-1)
--------------------
-2x + 2y + 3z = 0
2x + y - z = 3 (result of multiplying by -1)
--------------------add
3y + 2z = 3

-2x - y + z = -3
2x + 3y + 3z = 5
----------------add
2y + 4z = 2

2y + 4z = 2
3y + 2z = 3 --->(-2)
------------
2y + 4z = 2
-6y - 4z = -6 (result of multiplying by -2)
------------add
-4y = -4
y = 1

now sub 1 in for y in an equation where x has been eliminated
2y + 4z = 2
2(1) + 4z = 2
2 + 4z = 2
4z = 2 - 2
4z = 0
z = 0

now sub 1 in for y and 0 in for z in one of the original equations
-2x + 2y + 3z = 0
-2x + 2(1) + 3(0) = 0
-2x + 2 = 0
-2x = -2
x = 1

check..
-2x - y + z = -3
-2(1) - 1 + 0 = -3
-2 - 1 = -3
-3 = -3 (correct)

x = 1, y = 1 and z = 0
any questions ?

Answer 2

no thx I have another one could u help?

Answer 3

possibly...what ya got

Answer 4

2x + 2z = 4
2x = -2z + 4
x = -z + 2

-x - y - z = -8
-(-z + 2) - y - z = -8
z - 2 - y - z = -8
-2 - y = -8
-2 + 8 = y
6 = y

-4x + 4y + 5z = 7
-4(-z + 2) + 4(6) + 5z = 7
4z - 8 + 24 + 5z = 7
9z + 16 = 7
9z = 7 - 16
9z = -9
z = -1

2x + 2z = 4
2x + 2(-1) = 4
2x - 2 = 4
2x = 4 + 2
2x = 6
x = 3

check..
-x - y - z = -8
-3 - 6 - (-1) = -8
-9 + 1 = -8
-8 = -8 (correct)

x = 3, y = 6, and z - -1

Answer 5

thx

Answer 6

no problem....these are not really that hard, just time-consuming :)