Answer:
A) 90
Step-by-step explanation:
"The sum of two integers is 23" becomes
a + b = 23
"the positive difference of the same two integers is 13" becomes
a - b = 13 (difference means subtract)
Now solve the system..
a + b = 23
a - b = 13 *use addition or elimination method, since b has opposite coefficients...
2a = 36 ( we add the two equations together)
a = 18 (divide by 2 on both sides)
Since a = 18, 18 + b = 23, gives us b = 5. (18 + 5 = 23)
ab = (18)(5) = 90