Question

Which value of b would make 16x²-bx + 25 a perfect square trinomial?

Answer 1

Answer:

b = 40 and -40

Step-by-step explanation:

General form of Perfect square trinomial is a 2 + 2 a b + b 2

Therefore from 16 x 2 − b x + 25 a 2 = √ 16 x 2 , b 2 = 25 , then a = ± 4 x , b = ± 5 take consideration a=4x and b=-5 (different sign), then − b x = 2 ( 4 x ) ( − 5 ) − b x = − 40 x b = 40

The perfect square is ( 4 x − 5 ) 2 = 16 x 2 − 40 x + 25 .

if we consider a=4x and b=5 (same sign), then − b x = 2 ( 4 x ) ( 5 ) − b x = 40 x b = − 40

The perfect square is ( 4 x + 5 ) 2 = 16 x 2 + 40 x + 25 .

The first solution ( 4 x − 5 ) 2 is the best solution after comparing the expression given.  I hope this helps, xx .