Leo bought a used car for x dollars. one year later the value of the car was 0.88x. which expression is another way to describe the change in the value of the car?

It would be a 12% decrease. 0.88 is 88% (multiply by 100 to find the percentage) of the original price (x, which is 100%). as an example, say x=1000. 

0.88(1000)=880

880 is 88% of 1000, but the original price did not decrease by 88%/$880. Instead subtract this percentage from 100. 

100%-88%=12% 

there, you find the percentage lost/the percentage of the value decrease.