There are two solutions to this question, one is positive and the other is negative:
Answer:
x = 4 ± 
Step-by-step explanation:
Given
x² - 8x = 3
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(- 4)x + 16 = 3 + 16
(x - 4)² = 19 ( take the square root of both sides )
x - 4 = ±
( add 4 to both sides )
x = 4 ±
If the box if cubed for volume then lbh is 25x25x100=62500 cm ^3...if that's right. hope it helps any.