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3 years ago

If f(x) = 4x – 20, what is f(4)? A. –12 B. –4 C. 16 D. 4

Mathematics

2 answers:

galben [10]3 years ago

5 0

Answer: B. -4

Step-by-step explanation:

We are given the function : $f(x)=4x-20$

To find the value of f(4), we substitute the x equals to 4 in the above function and then simplify it to get the answer.

i.e. At x= 4 , $f(4)=4(4)-20$

Now, simplify the above expression, we get

$f(4)=16-20=-4$

Therefore, the correct option is Option (B.) -4 .

Lyrx [107]3 years ago

4 0

It's B. You enter 4 instead of x on the right side and see what you get.

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Find the following equation

adoni [48]

Answer:

$y=\frac{-1}{2}x+7$

Step-by-step explanation:

Slope intercept form: $y=mx+b$ when $m$ is the slope of the line and $b$ is the y-intercept (the y-coordinate of the point the line crosses the y-axis)

1) Find the slope ( $m$ )

$m=\frac{y_2-y_1}{x_2-x_1}$ when the points are $(x_1,y_1)$ and $(x_2,y_2)$

We can use any two points that the table gives us to plug into this equation. For example, we can use the points (14,0) and (0,7):

$m=\frac{0-7}{14-0}\\m=\frac{-7}{14}$

Simplify the fraction

$m=\frac{-1}{2}$

So far, our equation looks like this:

$y=\frac{-1}{2}x+b$

2) Find the y-intercept ( $b$ )

The y-intercept is the y-coordinate of the point the line crosses the y-axis, or in other words, it's the value of y when x is equal to 0.

Looking at the table, we can see that y is equal to 7 when x is equal to 0, so, therefore, $b=7$ .

Now, this is our final equation after plugging in $m$ and $b$ :

$y=\frac{-1}{2}x+7$

I hope this helps!

3 0

2 years ago

The function y=-16x^2+16x+32 represents the height in feet of a firework x seconds after it is launched

Nadya [2.5K]

Answer:

36feet

Step-by-step explanation:

Since we are not asked what to find, we can as well find the maximum height reached by the rocket

At max height, velocity is zero

V = dy/dx = 0

dy/dx = -32x + 16

0 = -32x+16

32x = 16

x = 16/32

x = 0.5s

Get the maximum height

y = -16(0.5)^2+16(0.5) + 32

y = -4+8+32

y = 36feet

Hence the max height reached by the rocket is 36feet

8 0

3 years ago

Kenny and Johnny went to the water park. Jonny brought $1.50 ice cream bar. Write an expression to represent the amount the two

Luba_88 [7]

P=2(1.50)
Since it is just the two of them it should he multiplied twice which would equal the total price "p".

5 0

3 years ago

Read 2 more answers

The average rate of change of f from 2 to 3

ella [17]

For a function of $f$ , the average rate of change can be found as follows:

$ARC=\frac{f(x_{2})-f(x_{1})}{x_{2}-x_{1}}$

So, this problem asks for the Average Rate of Change of $f$ from $x_{1}=2$ to $x_{2}=3$ . In this way, we need to find $f(x_{1}) \ and \ f(x_{2})$ . As you can see above, we have the graph of $f(x)$ , so we can find these values. Thus, from the graph: