Answer: the value of | 2x + y | = 1.39
the direction of 2x + y = 21° 
Step-by-step explanation:
Given that the vectors x and y are unit vectors that make and angle of 30 degrees with each other.
 Let assume that unit vector x is along the positive x-axis, and unit vector y is at +30°.
Therefore 
2x-y=
2< 1,0 > - < cos(30),sin(30) >
=<2-(√2)/2, 0-1/2>
and
|2x-y|=√((2-(√2)/2)² + (-1/2)^2)
=1.3862 
Therefore the value of | 2x + y | = 1.39
=atan((-1/2)÷(2-(√2)/2))
=atan(1.29289/-0.5)
=-0.369 radians
= -21.143° 
Therefore the direction of 2x + y is 
21° 
 
        
             
        
        
        
Answer:
Rational
Step-by-step explanation:
-9 is rational because 9 is a perfect square and all perfect squares are rational.
 
        
             
        
        
        
A dependent means t-test determines if the differences between scores on the pretest and post-test measures differ significantly from Zero(0).
Benefits of pre-test measurements
This design is superior to the post-test-only control design because it adds pre-tests. Addition of pre-test: Improve your design ability to detect effects. You can investigate the impact of interventions on various sublevels of pretesting.
The design of the pre-test and post-test is similar to the in-subject experiment. In this experiment, each participant is first tested in control conditions and then in therapeutic conditions.
 Learn more about pretesting. here: brainly.com/question/968894
#SPJ4
 
        
             
        
        
        
Answer:
y=-2x^2+10x-12
Step-by-step explanation:
graph is shown in image below
 
        
             
        
        
        
Answer:
Y= -2x +40
Step-by-step explanation: