Answer:
Step-by-step explanation:
the solution is right
x^2-6x-7=0:
x^2-6x-7=0
(add 7 to both sides)
x^2-6x=7
x^2-6x+9=7+9 (the coefficient of x² will be used to divide all sides)for here its 1, it will remain same ,
then we get the coefficient of x, divide it by 2 and square it and add it to both sides
which is like these
x²-6x=7
the coefficient of x is -6
-6/2 = -3, square it (-3)² = 9
then add 9 to both sides
x^2-6x+9=7+9
simplifiy the squares on the left hand side
x²+9 = (x-3)²
(x-3)^2=16
√(x-3)^2 )=±√16
x-3=± 4
x=-3±4
then simplify each sign
x=-3+4 x=-3-4
x=1 x=-7
Step-by-step explanation:
Divide 140 by
to represent the amount of hours he worked.
To make dividing easier,
can also represent 2.8 as a decimal.

He has worked 50 hours after completing 140 rows of grapes.
Answer:
3 strain would still alive after 48 hours
Step-by-step explanation:
Initial population of virus = 40000 grams
A certain virus is dying off at a rate of 18% per hour.
We are supposed to find how much of the strain would still be alive after 48 hours
Formula : 
=Initial population
N(t)= Population after t hours
r = rate of decrease = 18% = 0.18
t = time = 48 hours
So,the strain would still be alive after 48 hours=
Hence 3 strain would still alive after 48 hours
Answer:I think 0.4
Step-by-step explanation: Hope this helps
The answer is : impossible