Answer:
The correct option is;
A. The total points Shelly earned
Explanation:
The given details are;
The number of tasks completed by Shelly and Terrence in the game = x
The total points scored by Terrence = 20 less than the total point scored by Shelly
The expression for Terrence's total point is 90·x - 20
Let the total points Shelly earned = Y
Therefore since the total points scored by Terrence = 20 less than the total point scored by Shelly, we have;
The total points scored by Terrence = Y - 20
Comparing the two expressions for the total points scored by Terrence which are;
90·x - 20 and Y - 20 we have;
90·x - 20 = Y - 20
Adding 20 to both sides of the equation gives;
90·x - 20 + 20= Y - 20 + 20
Which gives;
90·x = Y
Therefore, the first term of the expression 90·x - 20, which is 90·x is equal to Y, which is the total points Shelly earned
The correct option is therefore the total points Shelly earned.