Question

question number 13....

Answer 1

Using a²-b²=(a-b)(a+b), and comparing, b=1/4

Answer 2

49x^2 - b =(7x + 1/2)(7x-1/2)
》by (a+b)(a-b)= a^2 - b^2
49x^2 -b = 49x^2 - 1/4
-b = 49x^2 - 49x^2 -1/4
-b = -1/4
b = 1/4