Answer:
Step-by-step explanation:
hello:
x²-4x=0 means : x(x-4)=0
x=0 or x-4=0
conclusion : x=0 and x= 4 ...answer : B
Answer:

Step-by-step explanation:
step 1
Find the area of the circle
The area of the circle is

we have
----> the radius is half the diameter
substitute


step 2
Find the area of a sector
Remember that
The area of the circle subtends a central angle of 360 degrees
so
using proportion
Find out the area of a sector with a central angle of 108 degrees

assume

substitute

If you multiply the top equation by -2 you get:
-4x -14y = 14 => -4x = 14+14y
now you can plug in the -4x into the second equation:
14+14y - 3y = -19 => 11y = -33 => y=-3
Fill in y=-3 in either equation to find x:
2x - 21 = -7 => 2x = 14 => x=7
So your ordered pair is (7,-3)
You know 1 is not a root because the sum of the coeffcients of the equation is 14, not zero.
It is fairly easy to try 3 by synthetic division (see attachment), which tells you that 3 is a root and the remaining quadratic factor is x²-3x-5. The quadratic formula tells you the roots of that factor are
... x = (-b±√(b²-4ac))/(2a) = (3±√29)/2
The appropriate choices are
... C. (3-√29)/2
... D. (3+√29)/2
... F. 3
_____
The quadratic formula tells you the solution to
... ax²+bx+c=0
is x = (-b±√(b²-4ac))/(2a)
We have a=1, b=-3, c=-5.