What is the answer for this equation?

What is always true when two whole numbers are subtracted?

An unknown number x is at most 10. which graph best represents all the values of x? number line graph with closed circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the right. number line graph with open circle on 10 and shading to the left. number line graph with closed circle on 10 and shading to the left.

Bc and bd are opposite rays. all of the following are true except a)a,b,c,d are collinear b)a,b,c,d are coplanar c)bc=bd d)b is between c and d