Answer:
a = -b/x
Explanation:
Solve this the way you solve any equation: undo the operations done to the variable, in reverse order.
Here, the variable (a) is multiplied by x, then b is added to the sum. So, first we undo the addition by subtracting b from the equation:
ax = -b
Now, we undo the multiplication by dividing the equation by x:
a = -b/x