If a=2 and b=3 , find the value of 2(a−b)+3(a+b)

My explanation would depend on the level of understanding of the person but one way would be the following:

We know that a = 2. Substitute the value of "a" in the given equation:

2(2-b)+3(2+b)

We know b = 3. Then substitute the value of "b" in the previous equation:

2(2-3)+3(2+3)

By order of operations, solve the operations inside the parenthesis first:

2(-1)+3(5)

Then we do the multiplications :

-2+15

Finally we complete the operation to get: 13