Which value of b would make 16x2bx+25 a perfect square trinomial?

1 Answer
Jan 11, 2017

b = 40 and -40

Explanation:

General form of Perfect square trinomial is a2+2ab+b2

Therefore from
16x2bx+25

a2=16x2,b2=25, then

a=±4x,b=±5

take consideration a=4x and b=-5 (different sign), then
bx=2(4x)(5)
bx=40x
b=40
The perfect square is (4x5)2=16x240x+25.

if we consider a=4x and b=5 (same sign), then
bx=2(4x)(5)
bx=40x
b=40
The perfect square is (4x+5)2=16x2+40x+25.

The first solution (4x5)2 is the best solution after comparing the expression given.