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just olya [345]

1 year ago

5

Find the value for b. 3x^2– X-10 =0

1 answer:

Greeley [361]1 year ago

3 0

Answer:

3x^2 -(6-5)x-10=0

3x^2 -6x+5x-10=0

3x(x-2)+5(x-2)=0

(x-2) (3x+5) = 0

either,

x -2 =0

x=2

then,

3x +5=0

x= -5/3

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3 tens 12 ones = tens 2 ones?

Tems11 [23]

Answer: tens 2 and ones 22

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1 year ago

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A piece of paper is to display ~128~ 128 space, 128, space square inches of text. If there are to be one-inch margins on both si

Grace [21]

Answer:

The dimensions of the smallest piece that can be used are: 10 by 20 and the area is 200 square inches

Step-by-step explanation:

We have that:

$Area = 128$

Let the dimension of the paper be x and y;

Such that:

$Length = x$

$Width = y$

So:

$Area = x * y$

Substitute 128 for Area

$128 = x * y$

Make x the subject

$x = \frac{128}{y}$

When 1 inch margin is at top and bottom

The length becomes:

$Length = x + 1 + 1$

$Length = x + 2$

When 2 inch margin is at both sides

The width becomes:

$Width = y + 2 + 2$

$Width = y + 4$

The New Area (A) is then calculated as:

$A = (x + 2) * (y + 4)$

Substitute $\frac{128}{y}$ for x

$A = (\frac{128}{y} + 2) * (y + 4)$

Open Brackets

$A = 128 + \frac{512}{y} + 2y + 8$

Collect Like Terms

$A = \frac{512}{y} + 2y + 8+128$

$A = \frac{512}{y} + 2y + 136$

$A= 512y^{-1} + 2y + 136$

To calculate the smallest possible value of y, we have to apply calculus.

Different A with respect to y

$A' = -512y^{-2} + 2$

Set

$A' = 0$

This gives:

$0 = -512y^{-2} + 2$

Collect Like Terms

$512y^{-2} = 2$

Multiply through by $y^2$

$y^2 * 512y^{-2} = 2 * y^2$

$512 = 2y^2$

Divide through by 2

$256=y^2$

Take square roots of both sides

$\sqrt{256=y^2$

$16=y$

$y = 16$

Recall that:

$x = \frac{128}{y}$

$x = \frac{128}{16}$

$x = 8$

Recall that the new dimensions are:

$Length = x + 2$

$Width = y + 4$

So:

$Length = 8 + 2$

$Length = 10$

$Width = 16 + 4$

$Width = 20$

To double-check;

Differentiate A'

$A' = -512y^{-2} + 2$

$A" = -2 * -512y^{-3}$

$A" = 1024y^{-3}$

$A" = \frac{1024}{y^3}$

The above value is:

$A" = \frac{1024}{y^3} > 0$

This means that the calculated values are at minimum.

<em>Hence, the dimensions of the smallest piece that can be used are: 10 by 20 and the area is 200 square inches</em>

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2 years ago

An ant moves forward 18 1⁄2 inches in one hour. It turns around and crawls

zvonat [6]

Answer:

The ant moved 10.75 in after three hours

Step-by-step explanation:

18.5-13.5=5+5.75=10.75

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7 0

2 years ago

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Question is below in picture

Ivan

It's $x^{2} +6x+1
/x(x+2)$ because this choice made the most since.

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2 years ago

solve |5x - 1| < 1 a. {x|0 < x < 2/5} b. {x|x < 0 or x > 2/5} c. {x|-2/5 < x < 2/5}

aliina [53]

<span>|5x - 1| < 1
-1 < 5x - 1 < 1
-1 + 1 < 5x < 1 + 1
0 < 5x < 2
0/5 < x < 2/5
0 < x < 2/5
</span>

8 0

2 years ago