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3 years ago

X2 + 4x - 21 = 0 quadratic formula

Mathematics

1 answer:

Elena-2011 [213]3 years ago

6 0

Answer:

Step-by-step explanation:

x2 +4x-21=0. solve for x

$x = \frac{7}{2}$

$x = 3 \frac{1}{2} \ x = 3.5$

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Can you answer #1 and #3 please (find the slope) ASAP

daser333 [38]

To calculate the slope of a line, you only need two points from that line, (x1, y1) and (x2, y2).

The equation used to calculate the slope from two points is:

(y2 - y1) / (x2 - x1)

#1:

First point : (5 ,7) = (x1, y1)

Second point : (2, -2) = (x2, y2)

Equation : (-2 - 7) / (2 - 5)

Solve the equation:

(-2 - 7) = -9

(2 - 5) = -3

-9/-3 = 3 (a negative number divided by a negative number gives you a positive number)

The slope of the line in #1 is : 3

#3:

First point : (5, 9) = (x1, y1)

Second point : (5, -2) = (x2, y2)

Equation : (-2 - 9) / (5 - 5)

Solve the equation:

In this case, you don't need to solve anything, because anything divided by zero will give you 0 (5 minus 5 = 0).

The slope of the line in #3 is : 0

8 0

3 years ago

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Quadrilateral ABCD is a rhombus with an area of 20 square inches.

Ugo [173]

Answer:

area of rhombus =1/2 d1×d2

20=1/2 ×10×d2

d2=4

intersection of diagonal make right angle and cut in equal parts

d1/2=10/2=5

d2/2=4/2=2

use Pythagoras in right angle to bide side

side^2= 5^2 +2^2

side = √29

8 0

3 years ago

Making coconut cookies. The recipe calls for 420 g of coconut and 120 g of sugar. Only has 252 g of coconut. How much sugar must

geniusboy [140]

Answer: 72 grams.

Step-by-step explanation:

Let be "s" the amount of sugar in grams that must be used for 252 grams of coconut to keep the same ratio of coconut to sugar.

Knowing that in the recipe for the coconut cookies, should be 420 grams of coconut and 120 grams of sugar, and you only have 252 grams of coconut, you can set up this proportion to find "s":

$\frac{420grams}{120grams}=\frac{252grams}{s}$

Now, you need to solve for "s":

$\frac{420grams}{120grams}=\frac{252grams}{s}\\\\s(\frac{420grams}{120grams})=252grams\\\\s=(252grams)(\frac{120grams}{420grams})\\\\s=72grams$

4 0

3 years ago

Which point lies on the circle represented by the equation (x+5) + (y-9) = 8

olga_2 [115]

Answer:

(-5,9+√8)

Step-by-step explanation:

There are two ways in which you can find a point that lies in the circle. One of them is to do y the subject of the formula, and another one is to determine the center of the circumference, and with the information of the radius, you can sum this value upward or downward.

the general equation of a circle is:

$(x-h)^2+(y-k)^2=r^2$

with center at (h,k)

you have the following equation:

$(x+5)^2+(y-9)^2=8\\\\h=-5\\\\k=9\\\\r=\sqrt{8}$

Then, the center is (-5,9)

if you sum the value of the radius in one of the fourth directions (up, down, left, right), for example upward you have

$(-5,9+r)=(-5,9+\sqrt{8})$

Then, one point that lies in the circle is (-5,9+√8)

3 0

3 years ago

Anyone help please!!!!

Andre45 [30]

We are to verify the identity:

cos(α-B)-cos(α+B) = 2 sinα sinβ

Left hand side = cos(α - B)-cos(α + B)

= cosα cosβ + sinα sinB - (cosα cosB - sinα sinβ)

= cosα cosβ + sinα sinB - cosα cosB + sinα sinβ)

= sinα sinβ + sinα sinβ

= 2 sinα sinβ

= Right Hand side

6 0

4 years ago

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