For this case we have to:
x: Represents the unknown number
y: Represents the exponent of base 10
So, considering a system of equations we have:

From the first equation we have:

Substituting in the second equation:

We choose the positive value:

So, the number is 0.4.
So:

Thus, the exponent is 5.
Answer:
Yara use 0.4 and
3.) 2 × 0.5 = 1
4.) -2 × -0.5 = 1
Answer: - 60i - 14j
Step-by-step explanation:
- 18i + 16j - 42i - 30j = - 60i - 14j
The answer is the first answer choice