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3 years ago

Which product is equivalent to -7 × 2/5?

Mathematics

1 answer:

ivanzaharov [21]3 years ago

4 0

Answer:

-2.8 or -14/5

Step-by-step explanation:

All you have to do is put the -7 over 1 and multiply across. So it'd look like:

-7/1 x 2/5 which works out across as -14/5 or you can convert it to a decimal to be -2.8. Hope this helps! :)

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mixer [17]

Answers:

a) 693 sq cm (approximate)
b) 48 sq cm (exact)

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Explanation:

Part (a)

A regular triangular pyramid, aka regular tetrahedron, has all four triangles that are identical copies of one another. They are congruent triangles. This will apply to part (b) as well.

To find the area of one of the triangles, we'll use the formula

A = 0.25*sqrt(3)*x^2

where x is the side length. This formula applies to equilateral triangles only.

In this case, x = 20, so

A = 0.25*sqrt(3)*x^2

A = 0.25*sqrt(3)*20^2

A = 173.20508 approximately

That's the area of one triangle, but there are four total, so the entire area is about 4*173.20508 = 692.82032 which rounds to 693 sq cm.

The units "sq cm" can be written as "cm^2".

----------------------------

Part (b)

We'll use the same idea as part (a). But the formula to find the area of one triangle is much simpler.

The area of one of the triangles is A = 0.5*base*height = 0.5*6*4 = 12 sq cm.

So the area of all four triangles combined is 4*12 = 48 sq cm

This area is exact.

The area of each 2D flat net corresponds exactly to the surface area of each 3D pyramid. This is because we can cut the figure out and fold along the lines to form the 3D shapes.

7 0

3 years ago

!!!!!!!!!!!!!!!!!!!!

notsponge [240]

Option 3

The solution for given expression is $\frac{(x - 4)(x - 4)}{(x + 3)(x + 1)}$

<h3><u>Solution:</u></h3>

Given that we have to divide,

$\frac{x^2 -16}{x^2 + 5x + 6} \div \frac{x^2 + 5x + 4}{x^2 -2x - 8}$ ---- (A)

Let us first factorize each term and then solve the sum

Using $a^2 - b^2 = (a + b)(a - b)$

$x^2 -16 = x^2 - 4^2 = (x + 4)(x -4)$ ----- (1)

$x^2 + 5x + 6 = (x + 2)(x + 3)$ ----- (2)

$x^2 + 5x + 4 = (x+1)(x + 4)$ ---- (3)

$x^2 -2x - 8 = (x-4)(x + 2)$ ---- (4)

Now substituting (1), (2), (3), (4) in (A) we get,

$\frac{(x + 4)(x -4)}{(x +2)(x +3)} \div \frac{(x+1)(x+4)}{(x-4)(x +2)}$

To do division with fractions, we turn the second fraction upside down and change the division symbol to a multiplication symbol at the same time. Then we treat this as a multiplication problem, by multiplying the numerators and the denominators separately.

$\frac{(x + 4)(x -4)}{(x +2)(x +3)} \times \frac{(x - 4)(x + 2)}{(x + 1)(x + 4)}$