Simplify -81m^2-17mn+15n^2+20m^2+3mn-17n^2+53m^2+18mn+7n^2

$- 81 m^{2} - 17 m n + 15 n^{2} + 20 m^{2} + 3 m n - 17 n^{2} + 53 m^{2} + 18 m n + 7 n^{2}$

Step 1

Add $- 81 m^{2}$ and $20 m^{2}$ .

$- 61 m^{2} - 17 m n + 15 n^{2} + 3 m n - 17 n^{2} + 53 m^{2} + 18 m n + 7 n^{2}$

Step 2

Add $- 61 m^{2}$ and $53 m^{2}$ .

$- 8 m^{2} - 17 m n + 15 n^{2} + 3 m n - 17 n^{2} + 18 m n + 7 n^{2}$

Step 3

Add $- 17 m n$ and $3 m n$ .

$- 8 m^{2} + 15 n^{2} - 14 m n - 17 n^{2} + 18 m n + 7 n^{2}$

Step 4

Subtract $17 n^{2}$ from $15 n^{2}$ .

$- 8 m^{2} - 2 n^{2} - 14 m n + 18 m n + 7 n^{2}$

Step 5

Add $- 2 n^{2}$ and $7 n^{2}$ .

$- 8 m^{2} + 5 n^{2} - 14 m n + 18 m n$

Step 6

Add $- 14 m n$ and $18 m n$ .

$- 8 m^{2} + 5 n^{2} + 4 m n$