3s = 5s - 10
-2s = -10
S = 5
S is the cost per pack in dollars
3x - 10 + x = 90
4x = 100
x = 25 degrees
Answer:
x ≈ - 9.41, x ≈ - 6.59
Step-by-step explanation:
Given
x² + 16x + 62 = 0 ( subtract 62 from both sides )
x² + 16x = - 62
To complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(8)x + 64 = - 62 + 64
(x + 8)² = 2 ( take the square root of both sides )
x + 8 = ±
( subtract 8 from both sides )
x = - 8 ± 
Hence
x = - 8 -
≈ - 9.41
x = - 8 +
≈ - 6.59
There will be excactly 400 fiction books. The ratio of fiction to all is 4 to 9, or 4 to 900.