Answer:
The number is 7
Step-by-step explanation:
certain positive number: x
x is multipled by 4:
4x
result of this is subtracted from the original number:
so original number minus 4x,
x - 4x
the result is 21 less than 0, this means negative 21
x - 4x = 0 - 21 = -21
do algebra:
-3x = -21
multiply both sides by -1
3x = 21
divide both sides by 3
x=7
(certain positive number: x) is equal to 7
Answer:
The hawk reaches the rabbit at t=4.3 sec
Step-by-step explanation:
Let
h ----> is the height in feet
t ----> is the time in seconds
v ---> the initial velocity in feet pr second
s ----- is the starting height
we have
when the hawk reaches the rabbit the value of h is equal to zero
we have
substitute
Solve the quadratic equation by graphing
The solution is t=4.3 sec
see the attached figure
D because those options do not intersect and are part of the universal set