Answer:
k = 16 , (4, 0 )
Step-by-step explanation:
Using the discriminant Δ = b² - 4ac
• b² - 4ac = 0 , then 2 real and equal roots
Here
y = x² - 8x + k
with a = 1, b = - 8, c = k , then
b² - 4ac
= (- 8)² - (4 × 1 × k)
= 64 - 4k , and equating to zero
64 - 4k = 0 ( subtract 64 from both sides )
- 4k = - 64 ( divide both sides by - 4 )
k = 16
Then
y = x² - 8x + 16
Equate to zero to find the root
x² - 8x + 16 = 0 ← left side is a perfect square
(x - 4)² = 0
x - 4 = 0 ( add 4 to both sides )
x = 4
The point on the x- axis is (4, 0 )
