Answer:
r = - 2.5

Step-by-step explanation:
21r - 7 - r + 5 = - 52
20r - 2 = - 52
20r - 2 + 2 = - 52 + 2
20r = - 50
20r ÷ 20 = - 50 ÷ 20
r = - 2.5
Answer:

Step-by-step explanation:
The given expression is:

We expand the parenthesis using the distributive property to obtain;

Recall that;

We apply this property and multiply out the constant terms to obtain;

Hi Kristian
a - 3b = 22
a = b - 2
We need to solve a = b -2 for a
First, we need to substitute b - 2 for a in a - 3b = 22
a - 3b = 22
b - 2 - 3b = 22
-2b - 2 = 22
-2b = 22 + 2
-2b = 24
b = 24/-2
b = -12
Now substitute -12 for b in a = b - 2
a = b -2
a= -12 - 2
a= -14
Thus, the solution is a = -14 and b = -12
The correct option is the last one (-14,-12)
If you have questions about my answer, please let me know.
Good luck!