Well, some integers can be irrational, but not all! :)
Answer: option d. the argument is valid by the law of detachment.
The law of detachment consists in make a conlcusion in this way:
Premise 1) a => b
Premise 2) a is true
Conclusion: Then, b is true
Note: the order of the premises 1 and 2 does not modifiy the argument.
IN this case:
Premise 1) angle > 90 => obtuse
Premise 2) angle = 102 [i.e. it is true that angle > 90]]
Conclusion: it is true that angle is obtuse
Let, the number = x
It would be: x + 15 = 2x - 56
2x - x = 15 + 56
x = 71
In short, Your Answer would be 71
Hope this helps!
Answer:
Y= 43, x=137, z=137 total is 360