X+y=8
y=8-x
3x+8-x=12
2x=12-8
2x=4
x=4:2
x=2
3*2+(8-2)=12
6+6=12
<span>1) 6-2x=8-3x
-2x+3x=8-6
x=2
2)3b+5=8b-15
8b-3b=5+15
5b=20
b=4
3) 11-5y=12-6y
-5y+6y=12-11
y=1
</span>
N( n + 1 ) + ( n + 1 ) = ( n + 1 )²
( n + 1 )( n + 1 ) = ( n + 1 )²
( n + 1 )² = ( n + 1 )²