Question

(3x - 4 ) ( 5x + 7 ) 15 X2 - as - 28

a =?

Answer 1

Answer:

Hence,

(3x−4)(5x+7)=15x

2

−ax−28

⇒15x

2

+21x−20x−28=15x

2

−ax−28

⇒15x

2

+x−28=15x

2

−ax−28

Equating the terms having similar powers:-

⇒x=−ax

⇒a=−1

⇒ Option B is correct