For this case we have the following data:


So that the figure can be a rectangle, its diagonals must be equal, that is, 
In this way we have:

Clearing x we have:


Thus, x must be equal to 10 so that the figure is a rectangle.
Answer:

Option A
Answer:

Step-by-step explanation:

Probability of drawing a heart from one deck:

Therefore, probability of drawing a heart from each of 3 decks:

It’s goes by 7.5
Just by looking at the chart you can see x-axis to y- axis for example, point for 2 ,you can divide to find out the answer. So it’s 7.5
b^2-4ac<0 b^2-144<0 (b-12)(b+12)<0
-12<b<12