Answer:
|−9|, −|−9| and −|9|
Step-by-step explanation:
Before we choose all the expression that is equal to -9, we must understand that the modulus of a value can return both its positive and negative value. For example, Modulus of b can either be +b or -b i.e |b| = +b or -b
Hence the following expression are all equal ro -9
a) |−9| is equivalent to -9 because the absolute value of -9 i.e |−9| can return both -9 and 9
b) −|−9| is also equivalent to -9. The modulus of -9 is also equal to 9, hence negating 9 will give us -9. This shows that −|−9| = −|9| = −9
c) −|9| is also equivalent to -9. This has been established in b above.
