Answer:
-10,10
Step-by-step explanation:
The given quadratic equation is

The discriminant of this equation is given by;

where a=k, b=20, c=k
For rational solutions, the discriminant must be zero.

Simplify to get:

This implies that:


Take square root to get:



Answer:
Step-by-step explanation: 252 apex
Answer:
160
Step-by-step explanation:
The measure of an arc is always twice the degree of the corresponding angle inside the circle. For example, the measure of arc DC is just double the measure of angle DOC; angle DOC is 44 degrees, so arc DC must be 88 degrees.
Angle COB is 80 degrees, so arc CB is 160 degrees.
Answer:
a. 720
b. 0.3
Step-by-step explanation:
a.
Three balls are selected at random without replacement.
First ball can be selected in 10 ways
Second ball can be selected in 9 ways
Third ball can be selected in 8 ways
Thus, there are 10×9×8 =720 different ways of selecting three balls.
b.
There are three cases that satisfy this condition
- first ball picked is 5, the others are not
- first ball is not 5, second is 5, third is not
- first and second ball is not five, third ball is 5
Each probabilities are:



Thus, one of the balls selected is the number 5 is then 
That is not correct. I just took the test and the answer is 2/3