Answer:
a) x = 13
b) x = 7
Step-by-step explanation:
A) Since they have the same base of 2 so
x + 4 + (-5) = 12
x - 1 = 12
x = 13
b) Since they have the same base of -3 so
8 + x + 4 = 19
x + 12 = 19
x = 7
