Answer:
x = 1 ± 
Step-by-step explanation:
Given
2x² - 4x = 10 ( divide through by 2 )
x² - 2x = 5
Using the method of completing the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(- 1)x + 1 = 5 + 1
(x - 1)² = 6 ( take the square root of both sides )
x - 1 = ±
( add 1 to both sides )
x = 1 ±
← exact solutions
For this case we can make the following rule of three:
1/10 scarf ------> 4/5 hour
x ------------------> 1 hour
Clearing the value of x we have:
x = (1 / (4/5)) * (1/10)
Rewriting we have:
x = (5/4) * (1/10)
x = 5/40
x = 1/8
Answer:
A fraction of a scarf that alison can knit in 1 hour is:
x = 1/8
N/8+4=28.
This is how you write out this equation.