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MArishka [77]
3 years ago
10

Solve for x x squared plus 4X minus 21 equals 0

Mathematics
2 answers:
iren2701 [21]3 years ago
7 0

Answer:

x = 3\\x = -7

Step-by-step explanation:

We have the following quadratic equation

x^2 + 4x - 21 =0

To solve the equation we must factor it.

To factor the equation we must find 2 numbers b and c that when adding them, you obtain as result 4 (c + b = 4) and when multiplying them, you obtain as result -21 (c * b = -21).

Then the polynomial will be factored in the following way:

(x+c)(x + b) = 0

You can verify that the numbers that meet this condition are:b = 7\\c = -3

So

x^2 + 4x - 21 =(x-3)(x + 7)=0

Finally the solutions are:

x = 3\\x = -7

suter [353]3 years ago
3 0

Answer:

x = -7 and x = 3

Step-by-step explanation:

x² + 4x - 21 = 0 factors as follows:  (x + 7)(x - 3) = 0.

Then x = -7 and x = 3.

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Write the standard form of an equation of an ellipse subject to the given conditions.
irina [24]

Answer:

The answer is below

Step-by-step explanation:

The standard form of the equation of an ellipse with major axis on the y axis is given as:

\frac{(x-h)^2}{b^2} +\frac{(y-k)^2}{a^2} =1

Where (h, k) is the center of the ellipse, (h, k ± a) is the major axis, (h ± b, k) is the minor axis, (h, k ± c) is the foci and c² = a² - b²

Since the minor axis is at (37,0) and (-37,0), hence k = 0, h = 0 and b = 37

Also, the foci is at (0,5) and (0, -5), therefore c = 5

Using c² = a² - b²:

5² = a² - 37²

a² = 37² + 5² = 1369 + 25

a² = 1394

Therefore the equation of the ellipse is:

\frac{x^2}{1369}+ \frac{y^2}{1394} =1

6 0
2 years ago
The town bought 36 kilograms of wood chips for their playgrounds.
olganol [36]
36 / 9 = 4
Answer : 4 play areas.
7 0
3 years ago
Lee has $1.75 in dimes and nickels. The number of nickels is 11 more than the number of dimes. How many of each coin does he hav
Schach [20]

Answer:

Lee has 19 nickels and 8 dimes

Step-by-step explanation:

hello, I think I can help you with this

Step 1

Let

value of a nickel=$0.05

value of a dime=$0.10

number of nickels=N

number of nickels=D

According to the question data Lee has $1.75 in dimes and nickels.

0.05N+0.1D=1.75,equation(1)

also, the number of nickels is 11 more than the number of dimes.mathematical speaking

N=11+D,equation(2)

Step 2

replace N from equation (2) into equation (1)

0.05N+0.1D=1.75

0.05(11+D)+0.1D=1.75

Now, solve for D

0.55+0.05D+0.1D=1.75

0.15D=1.75-0.55

D=1.2/0.15

D=8

Step 3

replace the value of D into equation(2) to obtain N

N=11+8

N=11+8

N=19

Hence, Lee has 19 nickels and 8 dimes

Have a great day.

5 0
3 years ago
17n=0.5n what is the value of n
alexandr402 [8]

Answer:

N=0

Step-by-step explanation:

If we wanted to answer the question mathematically, we could solve like so:

17n=0.5n

17n-0.5n=0.5n-0.5n

16.5n=0

n=0

6 0
3 years ago
Help me please ASAP!!!!
gogolik [260]
It took 8 weeks because follow 15 to the dot then go down and you see the answer

3 0
3 years ago
Read 2 more answers
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