Answer:
-7 = a
Step-by-step explanation:
1 = -1a -13/-6
multiply -6 on both sides
-6 = -1a - 13
add 13 on both sides
7 = -1a
divide -1 on both sides
-7 = a
explanations : When you do something on one side of the equation you have to do it on the other. Why add a 1 to -a (it is totally optional). You can add a 1 to a variable if it makes the equation easier (so the last step was optional as well)
