Question

Hey guys! I really need help with this Algebra question if that's okay. I want you to walk me through it, because I am so lost. This is for Algebra 2.
1. Solve the system by Elimination.
x + 5y - 4z = -10
2x - y + 5z = -9
2x - 10y - 5z = 0

A thank you in advance and whomever helps will receive medal :)

Answer 1

@bibby

Answer 2

for #2, you can just substitute z=5 into the other 2 equations

\(2x - y + z = -4 \implies 2x-y+5=-4\\2x-y=-9\)

\(-2x + 3y - z = -10 \implies -2x + 3y - 5 = -10\\-2x + 3y = -5\)

now our system looks like

\(2x-y=-9\\-2x+3y=-5\)

now we can solve one of the equations for a variable and the substitute to find the solution

\(2x-y=-9\\2x=y-9\\2x+9=y\)

replace that into the 2nd equation
\(-2x+3y=-5\\-2x+3(2x+9)=-5\\-2x+6x+27=5\\4x=-32\\x=-8\)

replace that into either equation to find y

\(2x-y=-9
\\-8*2-y=-9
\\-16-y=-9
\\-y=7
\\y=-7
\)

Answer 3

Thank you for helping on problem two :) @bibby

Answer 4

2x - y + 5z = -9
+
2x - 10y - 5z = 0
----------------
4x-11y=-9

having trouble doing the first one

Answer 5

That's okay, thank you for trying, @bibby :)