Question

(5n2 – 4nm - 9m²) + (7n2 + 4nm +8m²) =

Answer 1

Answer:

$\left(5n^2-4nm-9m^2\right)+\left(7n^2+4nm+8m^2\right)=12n^2-m^2$

Step-by-step explanation:

Given the expression

$\left(5n^2\:-\:4nm\:-\:9m^2\right)\:+\:\left(7n^2\:+\:4nm\:+8m^2\right)$

Remove parentheses: (a) = a

$=5n^2-4nm-9m^2+7n^2+4nm+8m^2$

Group like terms

$=5n^2+7n^2-4nm+4nm-9m^2+8m^2$

Add similar elements: $5n^2+7n^2=12n^2$

$=12n^2-4nm+4nm-9m^2+8m^2$

Add similar elements: $-4nm+4nm=0$

$=12n^2-9m^2+8m^2$

Add similar elements:  $-9m^2+8m^2=-m^2$

$=12n^2-m^2$

Therefore, we conclude that:

$\left(5n^2-4nm-9m^2\right)+\left(7n^2+4nm+8m^2\right)=12n^2-m^2$