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Nataliya [291]
3 years ago
8

Solve for x.

Mathematics
2 answers:
Ostrovityanka [42]3 years ago
3 0

Answer:

C.  3, -7

Step-by-step explanation:

x^2 +4x-21 =0

Factor

What 2 numbers multiply to -21 and add to 4

7*-3 = -21

7-3 = 4

(x+7) (x-3) =0

Using the zero product property

x+7 =0       x-3=0

x+7-7=0-7     x-3+3=0+3

x = -7            x=3

Arada [10]3 years ago
3 0

Answer:

<h2>C. 3, -7</h2>

Step-by-step explanation:

x^2+4x-21=0\\\\x^2+7x-3x-21=0\\\\x(x+7)-3(x+7)=0\\\\(x+7)(x-3)=0\iff x+7=0\ \vee\ x-3=0\\\\x+7=0\qquad\text{subtract 7 from both sides}\\x=-7\\\\x-3=0\qquad\text{add 3 to both sides}\\x=3

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45/14 as a decimal rounded to the nearest 10th
ozzi

Answer:

3.2

Step-by-step explanation:

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2 years ago
A rectangle has the following vertices. Find the area of the rectangle. (9, −1), (−1, 7), (−5, 2), (5, −6)
stiks02 [169]

Answer:  82 sq. units .

Step-by-step explanation:

Let A (9, −1), B (−1, 7), C(−5, 2), D(5, −6) are the vertices of rectangle.

Then we plot them on graph ( as provided in attachment)

Length = AB =\sqrt{(9+1)^2+(-1-7)^2} units  [By distance formula : \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}]

=\sqrt{(10)^2+(-8)^2}=\sqrt{100+64}=\sqrt{164}=2\sqrt{41} units

Width = BC = \sqrt{(-1+5)^2+(7-2)^2} units

=\sqrt{4^2+5^2}\\\\=\sqrt{16+25}\\\\=\sqrt{41}

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Hence, the  area of the rectangle is 82 sq. units .

7 0
3 years ago
A rectangle is removed from a right triangle to create the shaded region shown below. Find the area of the shaded region. Be sur
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6 0
3 years ago
Read 2 more answers
Dorian buys 2 pounds of almonds for $21.98 and 3 pounds of dried apricots for $26.25. Which is less expensive per pound? How muc
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Answer:

The apricots are less expensive per pound.

Step-by-step explanation:

Cost of 1 pound of almonds = 21.98/2

Cost of 2 pounds of almonds = $21.98

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3 years ago
Suppose 11 people arrive at a bank at the same time. In how many ways can they line up to wait for the next available teller?
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