Expand 3 brackets

Expand & Simplify three brackets. SUBTITLED
0:00 Intro
0:32 Change the order
0:46 Multiply 1st 2 brackets together
1:13 Multiply by 3rd bracket
1:56 Check answer

[justsomeone]

HIII !!
Thank you so much for your explanation!!
Can you please help with this :
A=

[michaelempeigne]

make life even easier by using the roots to do the multiplying : 2 * ( x + ( 1 / 2 ) ) * ( x + 5 ) ( x - 5 ) = 2 * [ x^3 + ( 5 - 5 + 1 / 2 ) * x^2 + [ ( 1 / 2 ) * ( 5 - 5 ) + 5 * ( - 5 ) ] * x + ( 1 / 2 ) * 5 * ( - 5 ) ]
so this makes 2 * [ x^3 + ( 1 / 2 )x^2 - 25x - 25 / 2 ] = 2x^3 + x^2 - 50x - 25