Simplify 3x^2+7xy+9x+(-8xy)+21x^2

$3 x^{2} + 7 x y + 9 x + (- 8 x y) + 21 x^{2}$

Step 1

Remove parentheses.

$3 x^{2} + 7 x y + 9 x - 8 x y + 21 x^{2}$

Step 2

Add $3 x^{2}$ and $21 x^{2}$ .

$24 x^{2} + 7 x y + 9 x - 8 x y$

Step 3

Subtract $8 x y$ from $7 x y$ .

$24 x^{2} - x y + 9 x$