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3 years ago

If f(x) = 4x² – 3x + 8, then f(-2) =

Mathematics

1 answer:

Citrus2011 [14]3 years ago

7 0

Answer: 30

Step-by-step explanation:

16+6+18

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which equation is represented by the function table below? x's are 1,2,3,4 y's are 8,14,20,26

Reika [66]

F: R -> R, f(x) = ax + b;
f(1) = 8 => a + b = 8;
f(2) = 14 => 2a + b = 14 => a = 6 and b =2;
f(3) = 20 => 6*3 + 2 = 20 True;
f(4) = 26 => 4*6 + 2 = 26 True;

then, f:R -> R, f(x) = 6x + 2;

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3 years ago

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The deck of a bridge is suspended 275 feet above a river. If a pebble falls off the side of the bridge, the height, in feet, of

Ivenika [448]

Answer:

Our equation for the height is:

y(t) = 275 - 16*t^2.

a) To find the average velocity between two times, t1 and t2, (where t2 > t1) the equation is:

$AV = \frac{y(t2) - y(t1)}{t2 - t1}$

Then:

i) t1 = 4s, t2 = 4s + 0.1s = 4.1s

The average velocity is:

$AV = \frac{(275 - 16*4.1^2) - (275 - 16*4^2)}{4.1 - 4} = \frac{16(4^2 - 4.1^2)}{0.1} = -129.6$

And the units will be ft/s, so the average speed is:

-129.6 ft/s

The minus sign is because te pebble is falling down.

ii) t1 = 4s, t2 = 4s + 0.05s = 4.05s

The average velocity is:

$AV = \frac{(275 - 16*4.05^2) - (275 - 16*4^2)}{4.05 - 4} = \frac{16(4^2 - 4.05^2)}{0.05} = -128.8$

So the average speed is -128.9 ft/s

iii) t1 = 4s, t2 = 4s + 0.01s = 4.01s

The average speed is:

$AV = \frac{(275 - 16*4.01^2) - (275 - 16*4^2)}{4.01 - 4} = \frac{16(4^2 - 4.01^2)}{0.01} = -128.16$

The average speed is -128.16 ft/s.

b) The instantaneous velocity of the pebble after 4 seconds can be obtained by looking at the velocity equation, that is the derivative of the height equation.

v(t) = dy(t)/dt.

v(t) = -2*16*t + 0

Then the velocity at t = 4s is:

v(4s) = -32*4 = -128

The instantaneous velocity at t = 4s is -128 ft/s.

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3 years ago

If the volume of the cylinder is represented by 5x2 + 15x + 2 and the height is 5x, which expression represents the area of the

Gwar [14]

Given:
V = 5x² + 15x + 2, the volume
h = 5x, the height

Let A = the area of the base.
Because V = Ah, therefore
A*(5x) = 5x² + 15x + 2
$A = \frac{5x^{2}+15x+2}{5x}$

Answer:
$A=x+3+ \frac{2}{5x}$

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4 years ago

Write 3729 correct to the nearest hundred.

tekilochka [14]

Answer:

<h2>3700 is the result of rounding 3729 to the nearest 100.</h2>

Step-by-step explanation:

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3 years ago

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What is the surface area of the right rectangular prism?

Mkey [24]