Simplify: (x + 7)(x-4) A. 2r +3 B. 12-28 C. x2-3x - 28 D. x2 + 3x - 28

Mathematics

1 answer:

jeka57 [31]2 years ago

7 0

Answer:

(x + 7)(x - 4) = x2 - 4x + 7x - 28 = x2 + 3x - 28

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nickel has an approximate diameter of 20 mm and an approximate thickness of 2 mm what is the approximate volume of a stack of 40

ziro4ka [17]

Answer:

The approximate volume of a stack of 40 nickels is 25132.741 cubic milimeters.

Step-by-step explanation:

A nickel can be modelled by the formula of a right cylinder, the approximate volume of the stack of nickels ( $V_{net}$ ), measured in cubic milimeters, is the product of the number of elements ( $n$ ), no unit, and the volume of each element ( $V$ ), measured in cubic milimeters. That is:

$V_{net} = n\cdot V$ (1)

By volume equation of right cylinder, we have the following formula:

$V_{net} = \frac{\pi}{4}\cdot n \cdot D^{2}\cdot h$ (2)

Where:

$n$ - Amount of nickels, no unit.

$D$ - Diameter of nickel, measured in milimeters.

$h$ - Thickness of nickel, measured in milimeters.

If we know that $n = 40$ , $D = 20\,mm$ and $h = 2\,mm$ , then the net volume of the stack of nickels is:

$V_{net} = \frac{\pi}{4}\cdot (40)\cdot (20\,mm)^{2}\cdot (2\,mm)$

$V_{net} \approx 25132.741\,mm^{3}$

The approximate volume of a stack of 40 nickels is 25132.741 cubic milimeters.

8 0

3 years ago

How to write two different pairs of decimals whose sums are 14.1. One pair should involve regrouping

Nitella [24]

To solve, first let’s define regrouping:
=> Regrouping involves carrying and borrowing during subtraction and addition of the given numbers.

So let us have the non-regrouping decimal number:
=> 8.4
Next, the other regrouping decimal
=> 5.7

So now let us show how it becomes 14.1:
8.4
+5.7
14.1

Starting from the right, 4 + 7 is equal 11, so bring down 1 and carry 1. Now 8+5 = 13, but 13 + carry 1 = 14
Thus, the answer is 14.1

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2 years ago

Evaluate 2z + xy when x = 4, y =6, and z =3 A.24 B.144 C.30 D.76

musickatia [10]

Answer:

Step-by-step explanation:

2z + xy

Put z as 3, x as 4, and y as 6.

2(3) + (4)(6)

Multiply the terms.

6 + 24

Add both terms.