-12 + 3x + 2 = 5x - 10 - 8x
-10 + 3x = -3x -10
-10 + 6x = -10
6x = 0
x = 0
Step-by-step explanation:
Z = 2x + 3
Putting value of x
Z = 2( - 16.7) + 3
Z = - 33.4 + 3
Z= - 30.4
Option B is the correct answer
Option D: 3.47*10^-7 is the correct answer
Step-by-step explanation:
In order to determine the number written in standard scientific notation, first of all we have to understand how the scientific numbers are written
the scientific numbers are written in the form of:

Here
a is a number between 1 and 10 while the value of n can be only integer (positive or negative)
so,
In the given options:
Option A has a number larger than 10 in place of a so it is not in standard notation
Option B has a number less than 1 in place of a so it is also not in standard notation
Option C has a number larger than 10 in place of a so it is not in standard notation
Option D is in standard scientific notation as 1<3.47<10 and the power of 10 is integer
Hence,
Option D: 3.47*10^-7 is the correct answer
Keywords: Scientific notation, exponents
Learn more about scientific notation at:
#LearnwithBrainly
Answer: 
Step-by-step explanation:
Let be "x" the amount of gasoline in liters that the car's tank had at the beginning of the trip.
1. In the first part of the trip the amount of gasoline the car used can be expressed as:

2. After the first part of the trip, the remaining was:
3. In the second part of the trip the car used
of the remaining. This is:

4. The total amount ot gasoline used in this trip was 20 liters.
5. Then, with this information, you can write the following equation:

6. Finally, you must solve for "x" in order to find its value. This is:
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hope it helps you ✌