Annika sells 6 inch pies for $5.00 and 8 inch pies for $9.00 each. Last week she sold twice as many 6 inch pies as she did 8 inch pies. She made $133.00 from her sales. Annika defined x as the number of 6 inch pies she sold and y as the number of 8 inch pies she sold. She wrote the system below. 6 x + 8 y = 133. 2 x = y.

Which statements about the system are true? Check all that apply.