Answer:
x = -20
Step-by-step explanation:
First we can rearrange the equation:
-18 = -28
2 *
- 18 = -28 * 2
The 2s canel out
x - 36 = - 56
x = -20
Answer:
The total resistance of these three resistors connected in parallel is 
Step-by-step explanation:
The attached image has the circuit for finding the total resistance. The circuit is composed by a voltage source and three resistors connected in parallel:
,
and
.
<u>First step: to find the source current</u>
The current that the source provides is the sum of the current that each resistor consumes. Keep in mind that the voltage is the same for the three resistors (
,
and
).



The total current is:


The total resistance (
) is the source voltage divided by the source current:

Now, replace
by the previous expression and the total resistance would be:

Simplify the expression and you must get:

The last step is to replace the values of the resistors:

Thus, the total resistance of these three resistors connected in parallel is 
Answer:

Step-by-step explanation:
A parabola has the following format:

If a is positive, it's minium value is:

In which

Factoring:
, in which
are the intercepts.
In this question:

So

Suppose a = 1, we have:


The minimum value will be:

We want this minimum value to be -4, which is 4 times the current minimum value, so we need to multiply a by 4. Then

And the parabola is:
