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3 years ago

Given f (x)=2x-10 for which value of x that f(x) = 8Help please!

Mathematics

1 answer:

Verizon [17]3 years ago

8 0

Answer:

x=9

Step-by-step explanation:

Plug in 8 for f(x)

8=2x-10

Isolate the x term by moving the 10

18=2x

Isolate the variable

9=x

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The cost of a car is $15,570. You plan to make a down payment of $1,500, and a monthly payment of $388.08 for 60 months.

sergiy2304 [10]

1. 15.570-1500= 14070. Yes it is B

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3 years ago

A rancher wishes to build a fence to enclose a 2250 square yard rectangular field. Along one side the fence is to be made of hea

Bess [88]

Answer:

The least cost of fencing for the rancher is $1200

Step-by-step explanation:

Let x be the width and y the length of the rectangular field.

Let C the total cost of the rectangular field.

The side made of heavy duty material of length of x costs 16 dollars a yard. The three sides not made of heavy duty material cost $4 per yard, their side lengths are x, y, y. Thus

$C=4x+4y+4y+16x\\C=20x+8y$

We know that the total area of rectangular field should be 2250 square yards,

$x\cdot y=2250$

We can say that $y=\frac{2250}{x}$

Substituting into the total cost of the rectangular field, we get

$C=20x+8(\frac{2250}{x})\\\\C=20x+\frac{18000}{x}$

We have to figure out where the function is increasing and decreasing. Differentiating,

$\frac{d}{dx}C=\frac{d}{dx}\left(20x+\frac{18000}{x}\right)\\\\C'=20-\frac{18000}{x^2}$

Next, we find the critical points of the derivative

$20-\frac{18000}{x^2}=0\\\\20x^2-\frac{18000}{x^2}x^2=0\cdot \:x^2\\\\20x^2-18000=0\\\\20x^2-18000+18000=0+18000\\\\20x^2=18000\\\\\frac{20x^2}{20}=\frac{18000}{20}\\\\x^2=900\\\\\mathrm{For\:}x^2=f\left(a\right)\mathrm{\:the\:solutions\:are\:}x=\sqrt{f\left(a\right)},\:\:-\sqrt{f\left(a\right)}\\\\x=\sqrt{900},\:x=-\sqrt{900}\\\\x=30,\:x=-30$

Because the length is always positive the only point we take is $x=30$ . We thus test the intervals $(0, 30)$ and $(30, \infty)$

$C'(20)=20-\frac{18000}{20^2} = -25 < 0\\\\C'(40)= 20-\frac{18000}{20^2} = 8.75 >0$

we see that total cost function is decreasing on $(0, 30)$ and increasing on $(30, \infty)$ . Therefore, the minimum is attained at $x=30$ , so the minimal cost is

$C(30)=20(30)+\frac{18000}{30}\\C(30)=1200$

The least cost of fencing for the rancher is $1200

Here’s the diagram:

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3 years ago

What is 7/7-1/5= ? Is it..... 8/12 18/35 28/35 6/35

Elza [17]

1-(1/5)= 4/5 or 28/35 if you multiply top and bottom by 5

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3 years ago

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GalinKa [24]

Answer:

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Step-by-step explanation:

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3 years ago

Point A is at (3, 2.7) and point B is at (3, 1.4) on a coordinate grid. The distance between the two points is ____. Input numbe

lisov135 [29]

The points have the same x-coordinate, so they lie on a horizontal line. The distance between them is the difference between their y-coordinates.

$2.7-1.4=1.3$

The distance between the two points is 1.3.

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3 years ago

Read 2 more answers

Given f (x)=2x-10 for which value of x that f(x) = 8Help please!​

Given f (x)=2x-10 for which value of x that f(x) = 8Help please!