Question

How do you simplify `-8( 4+ 5b ) + 9( 1+ 7b )`?

Answer 1

`-23+23b`

Explanation:

`-(8+5b)+9(1+7b)=-32-40b+9+63b=-23+23b`

Answer 2

`-23+23b=23b-23=23(b-1)`

whichever alternative is required

Explanation:

we use the distributive laws, then simplify by collecting like terms

`-8(4+5b)+9(1+7b)`

`-8xx4+ (-8)xx5b+9xx1+9xx7b`

`=-32-40b+9+63b`

`=-32+9-40b+63b`

`=-23+23b`

which can be factorised if required

`-23(1-b)`

Answer 3

`23b-23`

Explanation:

`"to simplify distribute brackets and collect like terms"`

`rArr-8(4+5b)+9(1+7b)`

`=color(red)(-32)color(blue)(-40b)color(red)(+9)color(blue)(+63b)`

`=color(blue)(+63b)color(blue)(-40b)color(red)(-32)color(red)(+9)`

`=color(blue)(23b)color(red)(-23)`