Help with this question please

How can you decide witch operations to use to slice a two step equation

If x + 10 = 70, what is x? a. 40 b. 50 c. 60 d. 70 e. 80

The frequency table shows the results of a survey comparing the number of beach towels sold for full price and at a discount during each of the three summer months. the store owner converts the frequency table to a conditional relative frequency table by row. which value should he use for x? round to the nearest hundredth. 0.89 0.90 0.92 0.96