Question

simplify: 3n²+n-[3(n-1)²+(n-1)]​

Answer 1

$3 {n}^{2} + n - (3 \: ( {n}^{2} + 1 - 2n) + n - 1) \\ = 3 {n}^{2} + n - (3 {n}^{2} + 3 - 6n + n - 1) \\ = 3 {n}^{2} + n - 3 {n}^{2} - 3 + 6n - n + 1 \\ = 6n - 2$