4x + 10 = 2x + 20
4x - 2x = 20 - 10
2x = 10
x = 5
The correct answer to your question is going to be option C. if we look at the equation 4x + 7 = 31, we can see that 4x stands for a number that changed depending on how much of something x can be. the 7 in the equation stands for something doesnt change depending upon variables how much or how little x will be. knowing this, if we look at option C we read that each phone case cost $7 while $4 is how much it costs to ship. since this problem is about how many $4 phone cases Taliba can get, C would incorrect because they say that $7 is the post of each phone case.
let me know if you have any further questions
:)
Probability =
(number of different successful results) / (number of all possible results) .
Number of marbles that are not blue = 7
Number of marbles in the bag = 10
Probability that one marble drawn at random is not blue = 7/10 = 70% .