Question 680353
Distribute the negative and the -2
-a - 3 = -2(2a) - 2(1) - 7
...
-a - 3 = -4a - 2 - 7
...
Group a variables ot one side of the equation
-a + 4a = -2 - 7 + 3
3a = -6
{{{highlight_green(a = -2)}}}
.....................
Have more questions? 
Email: HomeworkHelpers@readingboosters.com
Delighted to help.
-Reading Boosters
Website: www.MyHomeworkAnswers.com 
Wanting for others what we want for ourselves.