first speed --- x mph
return speed -- x+16 mph
6/x + 6/(x+16) = 1
times each term by x(x+16)
6(x+16) + 6x = x(x+16)
x^2 + 4x - 96 = 0
(x-8)(x+12) = 0
x = 8 or x is a negative
her first speed was 8 mph
her return speed was 24 mph
check:
6/8 + 6/24 = 1 , that's good!
The answer is B.
When you set up a ratio of all the corresponding sides, the ratios all equal 2:1
Answer:
x² + 4x + 20 = 12x - 5
x² + 4x - 12x + 20 + 5 = 0
x² - 8x + 25 = 0
Δ = √b² - 4ac
= √(-8)² - 4×1×25
= √64-100
= √(-36)
x ∉ R
