-2(4a^2-3[4a^2-(5b+a^2)]}

10a^2 - 30b

Step-by-step explanation:

-2(4a^2 - 3[4a^2 - (5b + a^2)]

We have three brackets in the expression, so we open the brackets after the other

Step1: let's open

[ 4a^2 - ( 5b + a^2)]

Open the bracket with - (minus)

- * 5b = -5b

- * +a^2 = -a^2

= [4a^2 - 5b - a^2]

Step 2: open the bracket

( 4a^2 - 3[4a^2 - 5b - a^2]

Open the bracket with -3

-3 * 4a^2 = -12a^2

-3 * -5b = + 15b

-3 * -a^2 = +3a^2

= (4a^2 - 12a^2 + 15b + 3a^2)

Step 3 : open the final bracket

-2(4a^2 - 12a^2 + 15b + 3a^2)

-2 * 4a^2 = -8a^2

-2 * -12a^2 = + 24a^2

-2 * + 15b = -30b

-2 * + 3a^2 = -6a^2

= -8a^2 + 24a^2 - 30b - 6a^2

Step 4: collect the like terms

= -8a^2 + 24a^2 - 6a^2 - 30b

= 10a^2 - 30b

2: 10

step-by-step explanation: