Question

If 49x^2 – b = (7x+5)(7x–5),then the value of b is:

Answer 1

Answer:

Step-by-step explanation:

ANSWER

(7x+  

2

1

​  

)(7x−  

2

1

​  

)=49x  

2

−b

⇒49x  

2

−  

4

1

​  

=49x  

2

−b                           (∵(a−b)(a+b)=a  

2

−b  

2

)

⇒b=  

4

1

​  

Answer 2

Answer:

49x²- b = (7x+5) (7x - 5)

49x²- b = 49² - 25

-b = 49x² ÷ 49x² - 25

-b = -25

b = 25