Question

Question 2(vii)
Factorise the following expressions
$10a^2-15b^2+20c^2$

Answer 1

$10a^2=2\times 5\times a\times a15b^2=3\times 5\times b\times b20c^2=2\times 2\times 5\times c\times cThecommonfactoris510a^2-15b^2+20c^2=(2\times 5\times a\times a)-(3\times 5\times b\times b)+(2\times 2\times 5\times c\times c)=5\left[\right(2\times a\times a)-(3\times b\times b)+(2\times 2\times c\times c\left)\right]=5(2a^2-3b^2+4c^2)$