Answer:
12.5%
Step-by-step explanation:
[First Value – Second Value] ÷ [(First Value + Second Value) ÷ 2] × 100
[50 - 30] ÷ [ 50 + 30] ÷ 2 × 100
20 ÷ 80 ÷ 2 × 100
0.25 ÷ 2 × 100
0.125 × 100
12.5 %
Step-by-step explanation:

but it's given = -4
which is incorrect
Again , 8^2 = 64
but it's given = √64
so option C and D are not true
Answer:
b
Step-by-step explanation: I dont have an explanation for u ho3