Question

How do you subtract `(4- 6d ^ { 2} ) - ( 9d ^ { 2} - 7)`?

Answer 1

`11-15d^2`

Explanation:

`4-6d^2-(9d^2-7)=4-6d^2-9d^2+7=11-15d^2`

Answer 2

`11-15d^2`

Explanation:

`"distribute brackets and "color(blue)"collect like terms"`

`"note that the second bracket is multiplied by "-1`

`1(4-6d^2)-1(9d^2-7)`

`=color(red)(+4)color(blue)(-6d^2)color(blue)(-9d^2)color(red)(+7)`

`=11-15d^2`