Question

15ab(a²-7a+10)/3b(a-2)
by factorisation method

Answer 1

15ab ( a^2 - 7a + 10 ) / 3b ( a -2 )
= 15ab ( a ^2 - 5a - 2a + 10 ) / 3b ( a - 2 )
= 15ab [ a ( a - 5 ) -2 ( a - 5 ) ] / 3b ( a - 2 )
= 15ab ( a - 2 ) ( a - 5 ) / 3b ( a - 2)
= 5a ( a - 5 )

Answer 2

Answer:

$\frac{15ab( {a}^{2} - 7a + 10) }{3b(a - 2)} \\ = \frac{5a \times \cancel{ 3b}( {a}^{2} - 7a + 10) }{ \cancel{ 3b}(a - 2)} \\ = \frac{5a( {a}^{2} - 7a + 10)}{a - 2} \\ = \frac{5a( {a}^{2} - 5a - 2a + 10)}{a - 2} \\ = \frac{5a(a(a - 5) - 2(a - 5))}{a - 2} \\ = \frac{5a((a - 5)(\cancel{a - 2}))}{ \cancel{ a - 2}} \\ = \underline{ \underline{ 5a(a - 5) }}$