How do you factor the expression #10x^2 - 90#?
1 Answer
Feb 6, 2016
10(x-3)(x+3)
Explanation:
in the expression
# 10x^2 - 90 # there is a 'common factor' of 10
hence
# 10x^2 - 90 = 10( x^2 - 9 )# inside the bracket there is a 'difference of squares '
In general :
# a^2 - b^2 = (a - b )( a + b ) #
# rArr 10x^2 - 90 = 10 (x - 3 )(x + 3 ) #
