The oxidation numbers of P, S and Br in HPO22-, H2S and NaBrO4 are, respectively?

Question

1, -1, +3
+1, -2, +7
+1, +2, +7
-1, -2, +7
-1, -2, +3

Answer 1

Math category? Okay:

+1 -1 +3 = 3
+1 -2 +7 = 6
+1 +2 +7 = 10
-1 -2 +7 = 4
-1 -2 +3 = 0

But I don't know the answer to your Chemistry question.

Answer 2

1
-2
+7

Answer 3

The right answer is +1, -2, +7
Basically:
1.For HPO2(-2) the O is -2x2=-4
The H is =1 and the total has to equal -2.
So -4+1+x=-2 and the answer is +1

2.For H2S, H=+1x2=+2
+2+x=0, and x=-2

3.For NaBrO4,
O=-2x4=-8
Na=1
-8+1+x=0, x=+7