Answer:
a = 9 + 6
Step-by-step explanation:
The subtraction equation we are given is a - 9 = 6
To get a version with the addition sign that means the same thing, all we have to do is to add 9 to both sides of the equals to sign.
<em>This is because whenever you want to add an arbitrary value to cancel out figures in an equation, you have to perform such an operation to both sides of the equation so that the equation will still remain balanced.</em>
This will give us.
a - 9 + 9 = 6 + 9
<em>from this, we can see that -9 + 9 = 0</em>
Hence, a = 6 + 9
This equation above means the same thing as the first.