25%=0.25
24*0.25=6
24-6=18
18 pairs are not black
        
                    
             
        
        
        
Answer:
See explanation
Step-by-step explanation:
16. Two parallel lines are cut by transversal. Angles with measures  and
 and  are alternate exterior angles. By alternate exterior angles, the measures of alternate exterior angles are the same:
 are alternate exterior angles. By alternate exterior angles, the measures of alternate exterior angles are the same:

Then

17. Two parallel lines are cut by transversal. Angles with measures  and
 and  are alternate interior angles. By alternate interior angles, the measures of alternate interior angles are the same:
 are alternate interior angles. By alternate interior angles, the measures of alternate interior angles are the same:

Then

18. Two parallel lines are cut by transversal. Angles with measures  and
 and  are alternate exterior angles. By alternate interior angles, the measures of alternate exterior angles are the same:
 are alternate exterior angles. By alternate interior angles, the measures of alternate exterior angles are the same:

Then

19. The diagram shows two complementary angles with measures  and
 and  . The measures of complementary angles add up to
. The measures of complementary angles add up to  then
 then

Hence,

Check:

20. Angles  and
 and  are vertical angles. By vertical angles theorem, vertical angles are congruent, so
 are vertical angles. By vertical angles theorem, vertical angles are congruent, so

Hence,

21.  and
 and  are supplementary. The measures of supplementary angles add up to
 are supplementary. The measures of supplementary angles add up to  so
 so

Therefore,

 
        
             
        
        
        
To figure this equation out, you'll have to divide 39 by 52% (0,52)
39 / 0.52 = 75
39 is 52% of 75 is your answer.
Hope this helps!
        
                    
             
        
        
        
5k3-3k+7-(-2k3+k2-9)
basically rewrite with simple algebra principles
15k-3k+7-(-6k+2k-9)
split up the parenthesis
15k-3k+7+6k-2k+9
sort them
15k-3k+6k-3k+7+9
short down by adding up the similar factors
answer: 18k+18
factorise
18(k+1)
both forms are right