Answer:
-7
Step-by-step explanation:
-7a + 1 = 15
1. Subtract 1 on both sides
-7a + 1 - 1 = 15 - 1
-7a = 14
2. Divide by -7 into both sides
-7a/-7= 14/-7
a = -7
Check:
Substitute the x with -7
-7(-7) + 1 = 15
* 2 negatives become a positive
14 + 1 = 15
15 = 15 CORRECT
Hope this helped!