Answer:
B
Step-by-step explanation:
There are two cases: Either f is the longest side or f is the shortest side. If we look at the first case, f < 12 + 19 which means f < 31. The second case tells us that 12 + f > 19 which means f > 7 so the answer is 7 < f < 31.
C.
(-1)*(-1)=1
1*(-1)= -1
first option (-1) is the right answer.
when you subtract a negative number from any platitude number the equation changes to addition so you would add the value of the negative number to 1.