Expand the following expression: -5x(x-7)(x+3)

Expansion of the given expression will result in x to the 3rd power, as there are 3 parts involving x, multiplied together. Let's ignore -5x for a second, and multiply the two expressions in brackets (using expansion rules of (a+b)(c+d) = ac + ad +bc +bd);
-5x(x-7)(x+3) = -5x(x^2 +3x - 7x -(7*3)) = -5x(x^2 -4x - 21).
We can now multiply each unit in the bracket by -5x, to get the final expression; (-5x * x^2) + (-5x * (-4x))  + (-5x * (-21)) = -5x^3 + 20x^2 + 105x

So the final answer is -5x^3 + 20x^2 + 105x

MS
Answered by Matas S. Maths tutor

4713 Views

See similar Maths GCSE tutors

Related Maths GCSE answers

All answers ▸

Solve this simultaneous equation for x: 3x + y = 10, x + y = 4


1i) solve x^2-4x-21=0


Factorise fully y=x^2+x-12 and hence find the roots of the curve


The width of a Rectangle is 4cm shorter than its length. the rectangle has an area of 32cm2. Calculate its perimeter?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences