Given:
{:
([1],color(white)("XXX"),,y,-2z," = ",-6),
([2],color(white)("XXX"),-4x,+y,+4z," = ",44),
([3],color(white)("XXX"),-4x,,+2z," = ",30)
:}
Subtract [3] from [2]
{:([4],color(white)("XXX"),color(white)("XXX"),y,+2z," = ",14):}
Subtract [1] from [4]
{:([5],color(white)("XXX"),color(white)("XXX"),color(white)("XX"),+4z," = ",20):}
Divide [5] by 4
{:([5],color(white)("XXX"),color(white)("XXX"),color(white)("XX"),z," = ",5):}
Substitute 5 for z in [1]
{:([6],color(white)("XXX"),color(white)("XXX"),y,-2(5)," = ",-6):}
Add 10 to both sides of [6]
{:([7],color(white)("XXX"),color(white)("XXX"),y,color(white)("XX")," = ",4):}
Substitute 5 for z in [3]
{:([8],color(white)("XXX"),-4x,color(white)("XX"),+2(5)," = ",30):}
Simplify
{:([9],color(white)("XXXXX"),x,color(white)("XX"),color(white)("XX")," = ",-5):}
