Suppose you bought a pizza for $8 you also bought a salad but you cannot remember how much you paid and you cannot find the receipt you know that the total amount you spent was $10 which equation would be best to use to find the cost of the salad a. 8+s=10 b.8+10=s c.8×s=10 d.10×s=$8

The correct option is A.
The cost of the pizza is $8 and the total amount spent is $10. To find the cost of the salad, all you have to do is to subtract the cost of the pizza from the total amount spent, the remain amount will be the cost of the salad. That is, 
Let S stands for salad,
8 + S = 10
S = 10 - 8 = 2
Thus, S = 2.
This means that, the salad costs $2.00