1) given
2) definition of linear pair
3) definition of linear pair and supplementary
4) definition of supplementary supplementary angles add to 180
5) the measure of angle one plus the measure of angle 2 plus the measure of angle 3 equals 180
6) substitution in lines 4 and 5
7) the measure of angle one plus the measure of angle 2 equals measure of angle 4 by algebra and simplification
Let the missing number be x
Mean is the total sum of data over the number of data therefore,
(11+20+x+3+1) / 5 = 9
Then simplify
(35 + x) / 5 = 9
Then multiply 5 to both sides
35 + x = 45
Then subtract 35 to both sides to find x
X= 10
Hope this helps!
X+4=2x+5
-1=x
hope this helps
1/5k+ 15
= 1/5k+ 15* (5/5) (because 5/5= 1)
= 1/5k+ (15*5)/ 5
= 1/5k+ 75/5
= 1/5k+ 75* (1/5)
= 1/5(k+ 75) (distributive property)
The final answer is 1/5(k+ 75).