Question

Find the product by applying the formula.

Formula : (x + a)(x + b) = x² + (a + b)x+ ab.

QUESTION :

(ax+by+5) (ax + by + 3)

= {(ax + by) +5} {(ax + by) + 3}
= (ax + by)² + (5 + 3) (ax +by) +5x3
= a²x² + b²y + 2abxy + 8ax + 8by + 15

THE QUESTION IS HOW DO WE GET +2abxy IN THE LAST LINE ?​

Answer 1

Answer:

coz (ax+by)^2 is in form (a+b)^2

where (a+b)^2=a2+b2+2ab

so,the ans has 2abxy

Answer 2

Hope this working helps.