Solution
a) Latoya's test score average Increased by 8 points this semester.
This simply means there is an increase of 8 points in Latoya's test score average.
Thus, a signed number that represents this change in average is +8 points
b) Isabel lost 70 dollars from her pocket.
This simply means there is a decrease in the money in Isabel's pocket.
Thus, a signed number to represent this change is -70 dollars