I'm not sure, but I knew that 12×12=144 so I guessed that it was 12×13 and checked what that was and it was 156, so I guess and check probably
Consider this:
If a test gives a positive result for an infected person 98% of the time, that means that 2% of the time, it gives a negative result for an infected person, which would be a false negative.
Then,
if the test is 97& accurate (not precise) for non-infected people, that means that it gives a negative result 97& of the time. So a positive result will be given 3% of the time for non-infected people, which is considered a false positive.
Calculator lolololol nah joking first
In order to prove this, you simply plug in the number 2 everywhere you see X:
4^(2) = 8(2).
Simplify
16 = 16 √
Since this checks out, x is proven to be 2.
2x - 4y = 10
7x - 9y = 12
_________
9x - 5y = 2