What is the value of f(−3)?

1.) Use the quadratic formula to solve the equation. If necessary, round to the nearest hundredth .x squared minus 21 x equals n

Andrew [12]

Part 1
We are given $x^2-21x=-4x$ . This can be rewritten as $x^2-18x=0$ .
Therefore, a=1, b=-18, c=0.
Using the quadratic formula
$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}=\frac{-\left(-18\right)\pm \sqrt{\left(-18\right)^2-4\left(1\right)\left(0\right)}}{2\left(1\right)}$
$x=\frac{18\pm 18}{2}$

The values of x are
$x_1=\frac{18-18}{2}=0$
$x_2=\frac{18+18}{2}=18$

Part 2
Since the values of y change drastically for every equal interval of x, the function cannot be linear. Therefore, the kind of function that best suits the given pairs is a quadratic function.

Part 3.
The first equation is $y=x^2+2$ .
The second equation is $y=3x+20$ .

We have
$x^2+2=3x+20$
$x^2-3x-18=0$
Factoring, we have
$\left(x-6\right)\left(x+3\right)=0$
Equating both factors to zero.
$x_1-6=0\rightarrow x_1=6$
$x_2+3=0\rightarrow x_2=-3$

When the value of x is 6, the value of y is
$y=3\left(6\right)+20=38$

When the value of x is -3, the value of y is
$y=3\left(-3\right)+20=11$

Therefore, the solutions are (6,38) or (-3,11)

7 0

2 years ago

12. Dominic drives a taxi. He charges a $2 flat fee plus $1.50 per mile.

r-ruslan [8.4K]

Answer:

The y-intercept represents the flat fee.

Step-by-step explanation:

The y-intercept on the graph would be the point at which the line cuts across or intercepts the y-axis. At this point, the value of x (miles travelled) would be 0. The y-intercept in this case, would be the flat fee which is given as $2.

At x = 0, f(0) = 2.

The y-intercept represents the flat fee on the graph of f(x).

5 0

3 years ago

You use a line of best fit for a set of data to make a prediction about an unknown value. The correlation coefficient for your d

Trava [24]

Answer:

Following are the solution to this question:

Step-by-step explanation:

For this set, the correlation coefficient is = -0.015.

It shows that financial variables have trust issues. Once a price rises, the other one is decreasing the value of -0,015 shows, that there are several fewer associations in the set of data among x and y and between y values. This interaction also can range between -1 to 1, to 0 being completely unrelated. But you'd never be sure, in this situation, 0.015 is very similar to 0.

It means that your prediction is nothing better than just a wild choice. Its odds of an estimated value being relatively close to the actual result are therefore much smaller as the points are it's hardly the best match.

4 0

2 years ago

James earned a total of $900 this week. this total was $20 less than four times the amount he earned last week. how much money d

Vladimir [108]

<span>4x – 20 = 900
4x = 900+20
4x = 920
x = 920/4
x = 230
he earned $230
</span>

7 0

3 years ago

The Pythagorean theorem is a2+b2=c2. Solve for b.

nata0808 [166]

Answer:

b = √c²-a²

Step-by-step explanation:

b² = c² - a²

b = √c²-a²

3 0

2 years ago