Question

Find coefficient of x2, x in product of (x - 5)(x + 3)(x + 7)​

Answer 1

Answer:

5

Step-by-step explanation:

Given---> ( x - 5 ) ( x + 3 ) ( x + 7 )

To find ---> Coefficient of x² in given product

Solution--->We know that,

( x + a ) ( x + b ) = x² + ( a + b )x + ab

Now,

( x - 5 ) ( x + 3 ) ( x + 7 )

Applying above identity, we get

= ( x - 5 ) { x² + ( 3 + 7 )x + 3 × 7 }

= ( x - 5 ) ( x² + 10 x + 21 )

= x ( x² + 10 x + 21 ) - 5 ( x² + 10x + 21 )

= x³ + 10 x² + 21x - 5x² - 50x - 105

= x³ + 5x² - 29x - 105

Coefficient of x² = 5

#Answerwithquality

#BAL

Answer 2

Answer:

Step-by-step explanation:

Given---> ( x - 5 ) ( x + 3 ) ( x + 7 )

To find ---> Coefficient of x² in given product

Solution--->We know that,

( x + a ) ( x + b ) = x² + ( a + b )x + ab

Now,

( x - 5 ) ( x + 3 ) ( x + 7 )

Applying above identity, we get

= ( x - 5 ) { x² + ( 3 + 7 )x + 3 × 7 }

= ( x - 5 ) ( x² + 10 x + 21 )

= x ( x² + 10 x + 21 ) - 5 ( x² + 10x + 21 )

= x³ + 10 x² + 21x - 5x² - 50x - 105

= x³ + 5x² - 29x - 105

Coefficient of x² = 5