Hiii Hope this helpsStep-by-step explanation:Step  1  :            b2 Simplify   ——            3  Equation at the end of step  1  :            b2            ((a2) -  (—— • a)) -  3b            3             Step  2  : Rewriting the whole as an Equivalent Fraction : 2.1   Subtracting a fraction from a whole Rewrite the whole as a fraction using  3  as the denominator :           a2     a2 • 3     a2 =  ——  =  ——————           1        3    Equivalent fraction : The fraction thus generated looks different but has the same value as the whole Common denominator : The equivalent fraction and the other fraction involved in the calculation share the same denominator Adding fractions that have a common denominator : 2.2       Adding up the two equivalent fractions Add the two equivalent fractions which now have a common denominator Combine the NUMERATORS together, put the sum or difference over the common denominator then reduce to lowest terms if possible: a2 • 3 - (ab2)     3a2 - ab2 ——————————————  =  —————————       3                3     Equation at the end of step  2  :  (3a2 - ab2)      ——————————— -  3b       3          Step  3  : Rewriting the whole as an Equivalent Fraction : 3.1   Subtracting a whole from a fraction Rewrite the whole as a fraction using  3  as the denominator :          3b     3b • 3    3b =  ——  =  ——————          1        3    Step  4  : PULLING out like terms : 4.1     Pull out like factors :   3a2 - ab2  =   a • (3a - b2)   Trying to factor as a Difference of Squares : 4.2      Factoring:  3a - b2   Theory : A difference of two perfect squares,  A2 - B2  can be factored into  (A+B) • (A-B) Proof :  (A+B) • (A-B) =         A2 - AB + BA - B2 =         A2 - AB + AB - B2 =         A2 - B2 Note :  AB = BA is the commutative property of multiplication. Note :  - AB + AB equals zero and is therefore eliminated from the EXPRESSION. Check :  3  is not a square !! Ruling : Binomial can not be factored as the difference of two perfect squares Adding fractions that have a common denominator : 4.3       Adding up the two equivalent fractions a • (3a-b2) - (3b • 3)     3a2 - ab2 - 9b ——————————————————————  =  ——————————————           3                      3        Trying to factor a multi variable polynomial : 4.4    Factoring    3a2 - ab2 - 9b   Try to factor this multi-variable trinomial using trial and error   FACTORIZATION fails Final result :  3a2 - ab2 - 9b  ——————————————        3