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Snowcat [4.5K]
3 years ago
6

Does anyone know this?!??

Mathematics
1 answer:
kondor19780726 [428]3 years ago
6 0

Indeed!

This is a quadratic equation, and there are several ways to factor this. I will try to explain the way I do it and try to make sense of it.

2x^2-x-15 - Original Equation

Now set up an X(as I cannot draw very well in brainly it will look bad)

 1        -3

     \ /

     / \

 2        5

This might all look very confusing so let me explain it.

First on the left side of the x, 1*2=2 which is the coefficient of the x^2 term.

The right side, -3*5=-15 which is the constant term.

What I did in the graph thing was to find 2 such pairs that line up in the graph in a way that the opposite corners multiplied and added together would = -1.

Such as the way I lined up the graph.

1*5(one of the diagonals) + 2*-3(the second diagonals)=5-6=-1 the coefficient of the middle term.

As long as you find 2 such pairs you got the answer, just write it from left it right then top to bottom.

The first ( ) would be (1x-3), the second ( ) would be (2x+5)

Now we can always switch the ( ) as in this problem we can write the answer as (x-3)(2x+5) or switch it around as (2x+5)(x-3).

Therefore the answer A is the correct answer.

**<u>If you have any questions about my explanation, simply ask me in the comment section and I will come answer. (I know my explanation here isn't the most clear so you probably will ask questions and please don't just put the answer in and be done with it, actually try to understand my explanation it will help with further questions like this.)</u>

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Show solutions please
slega [8]

Answer:

1. Their ages are:

Steve's age = 18

Anne's age = 8

2. Their ages are:

Max's age = 17

Bert's age = 11

3. Their ages are:

Sury's age = 19

Billy's age = 9

4. Their ages are:

The man's age = 30

His son's age = 10

Step-by-step explanation:

1. We make the assumption that:

S = Steve's age

A = Anne's age

In four years, we are going to have:

S + 4 = (A + 4)2 - 2 = 2A + 8 - 2

S + 4 = 2A + 6 .................. (1)

Three years ago, we had:

S - 3 = (A - 3)3

S - 3 = 3A - 9

S = 3A - 9 + 3

S = 3A – 6 …………. (2)

Substitute S from (2) into (1) and solve for A, we have:

3A – 6 + 4 = 2A + 6

3A – 2A = 6 + 6 – 4

A = 8

Substitute A = 8 into (3), we have:

S = (3 * 8) – 6 = 24 – 6

S = 18

Therefore, we have:

Steve's age = 18

Anne's age = 8.

2. We make the assumption that:

M = Max's age

B = Bert's age

Five years ago, we had:

M - 5 = (B - 5)2

M - 5 = 2B - 10 .......................... (3)

A year from now, it will be:

(M + 1) + (B + 1) = 30

M + 1 + B + 1 = 30

M + B + 2 = 30

M = 30 – 2 – B

M = 28 – B …………………… (4)

Substitute M from (4) into (3) and solve for B, we have:

28 – B – 5 = 2B – 10

28 – 5 + 10 = 2B + B

33 = 3B

B = 33 / 3

B = 11

If we substitute B = 11 into equation (4), we will have:

M = 28 – 11

M = 17

Therefore, their ages are:

Max's age = 17

Bert's age = 11.

3. We make the assumption that:

S = Sury's age

B = Billy's age

Now, we have:

S = B + 10 ................................ (5)

Next year, it will be:

S + 1 = (B + 1)2

S + 1 = 2B + 2 .......................... (6)

Substituting S from equation (5) into equation (6) and solve for B, we will have:

B + 10 + 1 = 2B + 2

10 + 1 – 2 = 2B – B

B = 9

Substituting B = 9 into equation (5), we have:

S = 9 + 10

S = 19

Therefore, their ages are:

Sury's age = 19

Billy's age = 9.

4. We make the assumption that:

M = The man's age

S = His son's age

Therefore, now, we have:

M = 3S ................................... (7)

Five years ago, we had:

M - 5 = (S - 5)5

M - 5 = 5S - 25 ................ (8)

Substituting M = 3S from (7) into (8) and solve for S, we have:

3S - 5 = 5S – 25

3S – 5S = - 25 + 5

-2S = - 20

S = -20 / -2

S = 10

Substituting S = 10 into equation (7), we have:

M = 3 * 10 = 30

Therefore, their ages are:

The man's age = 30

His son's age = 10

3 0
3 years ago
If the radius of a cone is 2 and the height is 4 what is the volume
laila [671]
Your answer: V≈16.76
4 0
3 years ago
Ms. Lynch has 21 coins in nickels and dimes.
bulgar [2K]

Answer:

Step-by-step explanation:So we know x + y = 21 and 5x +10y = 165 We line them up in columns    x +   y =   21  5x +10y = 165 To eliminate the x variable, I'll multiply every element in the 1st equation by -5. -5x + -5y = -105  5x + 10y =  165 Now we combine (add) the equations, which eliminates x altogether.  5y = 60   ...   y = 12 From there, x + 12 = 21  ...  x = 21-12  ...  x = 9 You should double check.  Do 9 nickles and 12 dimes equal $1.65? A very important thing to remember using this method is to do the same thing to each element in the equation that you change! I hope that helps.

4 0
2 years ago
EASY MATH!!! GIVING BRAINLIEST!!
musickatia [10]

Answer:

55

Step-by-step explanation:

So lets take our 50 dollars.

Next, take your increase of 5%. Remember, 5% is 0.05, and it is a increase of 5%, so we are multipling 50 by 1.05.

Before we start multiplying, lets recall that this occurs twice(2 years), but this doesnt mean we multiply 50 by 1.10. No, we just mutiply 50 by 1.05 2 times:

50*1.05

=

52.5

52.5*1.05

=

55.25

So your answer is 55 dollars(rounding down).

Hope this helps!

4 0
2 years ago
Can someone please explain how to solve 3x+3=x-1<br> will give brainiest :)
ollegr [7]
3x+3 = x-1
2x+3 = -1 (subtracted x from both sides)
2x = -4 (subtracted 3 from both sides)
x = -2 (divided 2 from both sides).
6 0
3 years ago
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