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3 years ago

7

An airplane flies 1920 miles in 3 hours. What is it’s average speed in miles per hour?

1 answer:

const2013 [10]3 years ago

3 0

Answer:

640

Step-by-step explanation:

you just divide

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Find number a and k so that x-2 is afactor<br>OF F(x)=x4-2ax tax-<br>X+k and F(-1)=3

Slav-nsk [51]

Question:

Find numbers a and k so that x-2 is a factor of

$f(x)=x^4-2ax^3+ax^2- x+k$

and

$f(-1)=3$

Answer:

$k = -2$ and $a=1$

Step-by-step explanation:

Given

$f(x)=x^4-2ax^3+ax^2- x+k$

$Factor:\ x - 4$

$f(-1)=3$

Required

Find a and k

For $f(-1)=3$

Substitute -1 for x

$f(x)=x^4-2ax^3+ax^2- x+k$

$f(-1) = (-1)^4 - 2a *(-1)^3 + a*(-1)^2 - (-1) + k$

$f(-1) = 1 - 2a *-1 + a*1 +1 + k$

$f(-1) = 1 +2a + a +1 + k$

$f(-1) = 2 +3a + k$

Substitute 3 for f(-1)

$3 = 2 +3a + k$

Collect Like Terms

$3 - 2 = 3a + k$

$1 = 3a + k$

Also:

If $x - 2$ is a factor, then

$f(2) = 0$

Substitute 2 for x and 0 for f(x)

$f(x)=x^4-2ax^3+ax^2- x+k$

$0 = 2^4 - 2a * 2^3 + a * 2^2 - 2 + k$

$0 = 16 - 2a * 8 + a * 4 - 2 + k$

$0 = 16 - 16a + 4a - 2 + k$

$0 = 16 - 12a - 2 + k$

Collect Like Terms

$2 - 16 = - 12a + k$

$-14 = k - 12a$

$k = 12a - 14$

Substitute 12a - 14 for k in $1 = 3a + k$

$1 = 3a + 12a - 14$

$1 = 15a - 14$

Collect Like Terms

$15a = 1 + 14$

$15a = 15$

Solve for a

$a = \frac{15}{15}$

$a=1$

Substitute 1 for a in $k = 12a - 14$

$k = 12 * 1 - 14$

$k = 12 - 14$

$k = -2$

3 0

2 years ago

Please help me on maths

Reika [66]

Answer:

x = 25

Step-by-step explanation:

x + 25 + 2x - 10 + 90 = 180

3x + 105 = 180

3x = 75

x = 25

5 0

3 years ago

Sarah drove for 39 miles with an average speed of 40 miles per hour. What amount of time was she driving for?

melamori03 [73]

1.53 hours if she drove 40 mph it would be 1 hour

6 0

3 years ago

What is the equation for f(x)

Paraphin [41]

F(x) = -5/6x - 3

You can get this by identifying the y-intercept and then using the formula for slope given any two points on the graph.

3 0

3 years ago

Find the coordinate of 4,1 translated 7 units left 2 units up

enot [183]

Answer:

(-3,3)

Step-by-step explanation:

4-7 is -3 and 1+2 is 3 so it is (-3,3)

6 0

3 years ago