John is j years old the product of his younger brothers and older sisters age is j^2-2j-15 how old are Jones, brother and sister, in terms of Jones age
Factorisation.
j² - 2 j - 15 = j² + 3 j - 5 j - 15 =
( j² + 3 j ) - ( 5 j - 15 ) =
j ( j + 3 ) - 5 ( j + 3 ) =
( j + 3 ) ( j - 5 ) =
( j - 5 ) ( j + 3 )
Brother is 5 yrs younger, sister u 3 yrs older.
My typo in second line.
j² + 3 j - 5 j - 15 is not
( j² + 3 j ) - ( 5 j - 15 )
j² + 3 j - 5 j - 15 = ( j² + 3 j ) - ( 5 j + 15 )