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EleoNora [17]
2 years ago
13

Factorise and solve x^2 + 4x -21 = 0

Mathematics
2 answers:
Korvikt [17]2 years ago
3 0

Answer:

(x + 7) (x - 3)

Step-by-step explanation:

Find 2 numbers that add to 4 and multiply to -21

(x + 7) (x - 3)

Ahat [919]2 years ago
3 0

Answer:

(x+7)(x-4) x=-7,4

Step-by-step explanation:

The factors of -21 that add up to 4 are 7 and -3, so put those as your two second values in your binomials and solve for x, in this case being the negative versions of the second term in the binomial

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A circular plate has circumference 32 inches. What is the area of this​ plate? Use 3.14 for pi. The area of this plate is about
Novosadov [1.4K]

Answer:

A = 82.53 in²

Step-by-step explanation:

We use the circumference equation C = 2πr and the area equation A = πr².

Using the first equation and the given circumference (32 in), we find the radius of the circle, and then use this result to find the area of the circle.

         

                                         C                            32 in

C = 2πr becomes r = ----------- and here r = ---------- = 5.10 in

                                        2π                            6.28

Then the area of the circle is A = πr², which here is A = 3.14(5.10 in)², which, when rounded off to two decimal places, is A = 82.53 in²

6 0
3 years ago
2.2x+3y=15.25 <br>4.6x+2.1y=18.325<br>USING ELIMINATION<br>SHOW WORK PLEASE
Artist 52 [7]

-4.6(2.2x+3y=15.25) = -10.12x - 13.8y = -70.15

2.2(4.6x+2.1y=18.325) = 10.12x - 4.62y = 40.315

simplify

-4.62y = -29.835

divide both sides by -4.62 to isolate y

y= 6.46

2.2x + 3 (6.46) = 15.25

2.2x + 19.38 = 15.25

subtract 19.38 to both sides

2.2x = -4.3

divide 2.2 to both sides

x= -1.95

I hope that this helped :)

4 0
2 years ago
Explain why f(x) = x^2+4x+3/x^2-x-2 is not continuous at x = -1.
liberstina [14]

Answer:

The value of x = -1 makes the denominator of the function equal to zero. That is why this value is not included in the domain of f(x)

Step-by-step explanation:

We have the following expression

f(x) = \frac{x^2+4x+3}{x^2-x-2}

Since the division between zero is not defined then the function f(x) can not include the values of x that make the denominator of the function zero.

Now we search that values of x make 0 the denominator factoring the polynomial x^2-x-2

We need two numbers that when adding them get as a result -1 and when multiplying those numbers, obtain -2 as a result.

These numbers are -2 and 1

Then the factors are:

(x-2) (x + 1)

We do the same with the numerator

x^2+4x+3

We need two numbers that when adding them get as a result 4 and when multiplying those numbers, obtain 3 as a result.

These numbers are 3 and 1

Then the factors are:

(x+3)(x + 1)

Therefore

f(x) = \frac{(x+3)(x+1)}{(x-2)(x+1)}

Note that \frac{(x+1)}{(x+1)}=1 only if x \neq -1

So since x = -1 is not included in the domain the function has a discontinuity in x = -1

3 0
3 years ago
What is 1/4 times 2/4
boyakko [2]
1/4= 0.25
2/4= 1/2 = 0.5
0.25 x 0.5 = 0.125
0.125 = 1/8
8 0
3 years ago
A rental car company charges $63.41 per day to rent a car and $0.05 for every mile driven. Ella wants to rent a car, knowing tha
zvonat [6]

Answer:

2 days

Step-by-step explanation:

275 miles times 0.05 = $13.75 for mileage

200-13.75=186.25 left

186.25/63.41(daily fee)= 2.93

She can rent it for 2 days

6 0
1 year ago
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