Why is 3+(-5) equal to -2

Mathematics

2 answers:

photoshop1234 [79]2 years ago

6 0

Here's an example: 3/5 divided by 7/8.

3/5

_____

7/8

Let's do it WRONG, to see why that's bad. Here's our example, multiplied by something that ISN'T equal to one:

3/5 1 3/5 3/5

_____ * _____ = _______ = ______ = 3/5

7/8 8/7 56/56 1

Multiplying 7/8 by 8/7 turns our denominator into 1, which seems helpful. But it leaves us with the same numerator we started with. Can this be right? Is 3/5 divided by 7/8 equal to 3/5 divided by one, so that 7/8 = 1? Oops, that has to be wrong.

For comparison, here's the RIGHT way:

3/5 8/7 24/35 24/35

_____ * _____ = _______ = _______ = 24/35

7/8 8/7 56/56 1

In this case, what we multiplied by, 8/7 divided by 8/7, is equal to one, because anything divided by itself is equal to one. But 1 over 8/7, which we used up above in the first example, is NOT equal to one, which means that if we use 1 over 8/7, we change our question. We may get an answer, but it won't be the right one.

Svetradugi [14.3K]2 years ago

4 0

Answer:

Step-by-step explanation:

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Plz help with this math. Can't find the area of the triangular faces.

Zina [86]

First of all, you have to find the area of both triangles:
$\frac{bh}{2}$
$\frac{4*4}{2}$
Or just 16 because there are 2 of the same triangles.

Now you have to find the area of the 3 rectangles.

The two that are in the front are 4*3 (l*h) or 12*2 (because there are 2 congruent rectangles. The area of those rectangles is 24 square mm.

Now you find the area of the back rectangle:
5.7*3 = 17.1

Finally, you add all the found numbers to figure out the surface area.
17.1 + 16 + 24 = 57.1 square millimeters.

Hope this helped,
Loafly

4 0

3 years ago

I need some help!!!!!!!!!!!!!!!!!!!!!!!

vampirchik [111]

Step-by-step explanation:

We are dealing with theoretical probability. This means that our probability of said outcome is

$\frac{x}{y}$

where x is the outcome we want, and y is the total number of outcomes possible.

28. There is 3 triangles out of 6 polygons so the probability is 1/2.

29.There is 1 Pentagon so the probability is 1/6.

30. This is a complement to question 28. A complement is the inverse of the problem. A complement and its original add to 1 so the probability of both getting a triangle is 1/2.

31. There is 4 non quadraletrial so the probability is 2/3.

32. There is 3 figures that has more sides than three so 1/2 is the probability.

33.There is only multi right angles figures so 1/2 is the probability.

34. There is 30 days in April so the probability it's the 29th is

$\frac{1}{30}$