Answer: x = -5
Step-by-step explanation:
1) subtract 4 from both sides (-5x = 25)
2) divide -5 from both sides (x = -5)
Then you have the answer!
Step-by-step explanation:

Correct answer; A right angle
This problem is an example of an arithmetic series.
The common difference of the second term (15) with the first term (9) and the third term (21) with the second term (15) [15-9=6; 21-15=6] is 6.
The formula for solving this is:
An= A1 +(n-1)*d where An is the nth term, A1 is the first term, n is the number of terms and d is the common difference.
An=9+ (31-1)*6 = 189
The answer is 189.
It’ll be 20.
12+28+15+25+20=100
100/5= 20
Add all the numbers and then divide by the total amount of numbers there and that’s your answer