Answer:
8.4 dollars
Step-by-step explanation:
The error is in the resolution of the proportion. In fact, the initial proportion is correct:

where x is the total cost. However, the following step of the resolution is wrong. In fact, the correct resolution is the following:
- Multiplying by x on both sides:

- Multiplying by 3.5 no both sides:

And now we can find x:

So, the total cost is 8.4 dollars.
Answer:
The Solution Set
Step-by-step explanation:
Despite missing some context, the output we could get as result of an expression/equation it is what we call a Solution set. A set which makes the initial statement of equation/expression true, therefore valid.

Therefore, the elements of the Solution set, 3 and 4 when plugged into the equation make the statement of the quadratic equation true.

Answer:
-16
Step-by-step explanation:
14=6+z/-2
14-6=z/-2
8=z/-2
z=8*-2
z=-16
Answer:
2.6
Step-by-step explanation:
Let us assume that the unit of measurement is centimetre (cm)
To obtain the value of A, do the following:
From the diagram above, we can say that the scale is 5 cm to 1 unit since there are 5 lines before a number.
Next, we shall determine the value of 1 cm.
5 cm = 1 unit
Therefore,
1 cm = 1/5 = 0.2 unit
This means that 1 small line is equivalent to 0.2 unit.
Now we shall determine A as follow:
A is exactly 3 lines (3 cm) after number 2.
1 cm = 0.2 unit
3 cm = 3 x 0.2 = 0.6 unit
Now, add 0.6 to 2 to obtain the value of A.
A = 2 + 0.6
A = 2.6
Therefore, A correspond to 2.6