Ax^2+bx=c
REMEMBER THIS
ok
first, make sure that a is 1
done
now take 1/2 of b and square it
-18/2=-9, (-9)^2=81
add that to both sides
x²-18x+81=19+81
x²-18x+81=99
factor perfect square
(x-9)²=100
square root both sides
don't forget positive and negative root
x-9=10
x-9=-10
ad 9 to both sides
x=19
x=-1
answer is -1; 19
2nd choice is answer
I think it would best be displayed as a line plot.
1.
In line with the test each person who came into interaction
with the infected person will become infected also. With this information, the
calculation would be: 9 people each day for 7days would be equivalent to 9 x 7
which equals 63 people.
2.
Here were 7 other people in the experiment if patient
zero is left out. If each person intermingled with 6 different people every day
in 7 days then the calculation would be: 7 people infected x 6 new people = 42
infected people each day
42 new people every day x 7 days = 294
infected persons.
Answer:
Let the distance of school and house is x k m
Then time taken at speed 2.5 km\hr=
2.5
x
hr
And time taken at speed 4 km\hr=
4
x
hr
∴
2.5
x
−
4
x
=
60
12
⇒
10
4x−2.5x
=
5
1
⇒x=3 km
Then the distance of school and house is 3 k m
may this help you
