Answer:
x = -9
Explanation:
-15x - 40 = 23 - 8x
add 8x to both sides to bring -8x to the left side
-15x + 8x - 40 = 23
add 40 to both sides to bring -40 to the right side
-15x + 8x = 23 + 40
add the common terms
-7x = 63
for x to be alone divide -7 to both sides
x = -9
I hope this helped!