[tex]3x+2y=20\\3*2+2*n=20\\6+2n=20\\2n=20-6\\2n=14\\n=7[/tex]

( 2 ; n )

3x + 2y = 20

3 × 2 + 2n = 20

6 + 2n = 20

2n = 20 - 6

2n = 14

n = 14 ÷ 2

n = 7