Question

How do you do this question?

Answer 1

Answer:

positive

Step-by-step explanation:

Find the sign of (2-2x+y) for any point (x,y) in quadrant 2.

In quadrant 2, the x's are negative and the y's are positive.

So choose a negative value for x and a positive value for y and evaluate:

2-2x+y

Let's try (-4,5):

2-2(-4)+5

2+8+5

15 (positive)

Let's try(-1/2 , 10):

2-2(-1/2)+10

2+1+10

3+10

13 (positive)

Let's try in general Let (x,y)=(-a,b) where a and b are positive:

2-2(-a)+b

2+2a+b

Since a and b are positive, then 2+2a+b is positive because you are adding three different positive numbers.