Answer:
b = 16
Step-by-step explanation:
16*x + b*x + 4 = 0
Solving for x we get:
x₁,₂ = - b ± √ b² - 4*a*c ] / 2*a (1)
If we take a look to the square root
√ b² - 4*4*16 = √ b² - 256
if we make √ b² - 256 = 0
b² = 256 ⇒ b = 16
Then equation (1) becomes:
x₁,₂ = ( - 16 ± 0 ) / 32
x = - 1/2