Expand and simplify (x − 4)(2x + 3y)^2

Rewrite (x − 4)(2x + 3y)2 as (x - 4)(2x + 3y)(2x + 3y)
Multiply out the first two brackets to give -(2x2 + 3xy - 8x2 - 12y)(2x + 3y)
Multiply out the remaining brackets4x3 + 6x2y - 16x2 - 24xy + 24xy + 6x2y + 9xy2 - 24xy - 36y2
Simply what's left...4x2 + 12x2y + 9xy2 – 16x2 – 48xy – 36y2
Therefore...(x − 4)(2x + 3y)2 = 4x2 + 12x2y + 9xy2 – 16x2 – 48xy – 36y2

HK

Related Maths GCSE answers

All answers ▸

How to complete the square to solve quadratic equations?


Write x^2 + 8x + 7 in the form (x + a)^2 + b


How do I solve simultaneous equations by substitution?


Solve the following simultaneous equations: 6j+4k=40; 7j-3k=-7