Răspuns :
10·[x-10·(216+10·30)]=1000
10·(x-10·516)=1000
=x-10·516=1000÷10
=x-10·516=100
=x-10=516÷100
=x-10=5,16
x=10+5,16
x=15,16
10·(x-10·516)=1000
=x-10·516=1000÷10
=x-10·516=100
=x-10=516÷100
=x-10=5,16
x=10+5,16
x=15,16