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3 years ago

If a² + a + 1=0, find the value of 1 - a -a².

Mathematics

1 answer:

IRINA_888 [86]3 years ago

7 0

Answer:

Step-by-step explanation:

Given: a² +a +1= 0

Bringing a terms to the right-hand side:

1= -a² -a

-a² -a= 1

-a -a²= 1

1 -a -a²

= (-a -a²) +1

= 1 +1

= 2

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Solve for f: 6f + 9g = 3g + f

andrezito [222]

Answer:

f= -(6/5)g

Explanation:

We have been given the expression 6f+9g = 3g+f

Solve for f means find the value of f

We will simplify the given expression:

we will collect the values of f at one side and g on the other side

So, rewriting the given expression 6f+9g =3g+f as 6f-f=3g-9g

So, after simplification it will lead to 5f= -6g

After further simplification f= -(6/5)g which is the final result

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3 years ago

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Can someone do my last question and actually try it

MariettaO [177]

Answer:

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Step-by-step explanation:

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3 years ago

If the area of the rectangle is 90 km?, then what is the value of the missing side?

r-ruslan [8.4K]

I believe it would be B.
Logically, it’s the only one that makes sense,
As 9x10= 90
None of the others have any way to divide or multiply up to the area,
So yes, B.

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3 years ago

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Find one value of x that is a solution to the equation:<br>(x^2– 8)^2 + x^2 – 8 = 20<br>x=

Kipish [7]

Answer:

x = 2 sqrt(3) or x = -2 sqrt(3) or x = sqrt(3) or x = -sqrt(3)

Step-by-step explanation:

Solve for x:

-8 + x^2 + (x^2 - 8)^2 = 20

Expand out terms of the left hand side:

x^4 - 15 x^2 + 56 = 20

Subtract 20 from both sides:

x^4 - 15 x^2 + 36 = 0

Substitute y = x^2:

y^2 - 15 y + 36 = 0

The left hand side factors into a product with two terms:

(y - 12) (y - 3) = 0

Split into two equations:

y - 12 = 0 or y - 3 = 0

Add 12 to both sides:

y = 12 or y - 3 = 0

Substitute back for y = x^2:

x^2 = 12 or y - 3 = 0

Take the square root of both sides:

x = 2 sqrt(3) or x = -2 sqrt(3) or y - 3 = 0

Add 3 to both sides:

x = 2 sqrt(3) or x = -2 sqrt(3) or y = 3

Substitute back for y = x^2:

x = 2 sqrt(3) or x = -2 sqrt(3) or x^2 = 3

Take the square root of both sides:

Answer: x = 2 sqrt(3) or x = -2 sqrt(3) or x = sqrt(3) or x = -sqrt(3)

8 0

3 years ago

Choose 5 cards from a full deck of 52 cards with 13values (2, 3, 4, 5, 6, 7, 8, 9, 10, J, Q, K, A) and 4 kinds(spade, diamond, h

Delvig [45]

Answer:

a) 182 possible ways.

b) 5148 possible ways.

c) 1378 possible ways.

d) 2899 possible ways.

Step-by-step explanation:

The order in which the cards are chosen is not important, which means that we use the combinations formula to solve this question.

Combinations formula:

$C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

In this question, we have that:

There are 52 total cards, of which:

13 are spades.

13 are diamonds.

13 are hearts.

13 are clubs.

(a)Two-pairs: Two pairs plus another card of a different value, for example:

2 pairs of 2 from sets os 13.

1 other card, from a set of 26(whichever two cards were not chosen above). So

$T = 2C_{13,2} + C_{26,1} = 2*\frac{13!}{2!11!} + \frac{26!}{1!25!} = 182$

So 182 possible ways.

(b)Flush: five cards of the same suit but different values, for example:

4 combinations of 5 from a set of 13(can be all spades, all diamonds, and hearts or all clubs). So

$T = 4*C_{13,5} = 4*\frac{13!}{5!8!} = 5148$

So 5148 possible ways.

(c)Full house: A three of a kind and a pair, for example:

4 combinations of 3 from a set of 13(three of a kind ,c an be all possible kinds).

3 combinations of 2 from a set of 13(the pair, cant be the kind chosen for the trio, so 3 combinations). So

$T = 4*C_{13,3} + 3*C_{13.2} = 4*\frac{13!}{3!10!} + 3*\frac{13!}{2!11!} = 1378$

So 1378 possible ways.

(d)Four of a kind: Four cards of the same value, for example:

4 combinations of 4 from a set of 13(four of a kind, can be all spades, all diamonds, and hearts or all clubs).

1 from the remaining 39(do not involve the kind chosen above). So

$T = 4*C_{13,4} + C_{39,1} = 4*\frac{13!}{4!9!} + \frac{39!}{1!38!} = 2899$

So 2899 possible ways.

4 0

3 years ago

If a² + a + 1=0, find the value of 1 - a -a².​

If a² + a + 1=0, find the value of 1 - a -a².