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Marina86 [1]
3 years ago
11

This is Adele's solution for the equation x^2 + 8x - 9 = 0 Step 1 x^2 + 8x - 9 = 0 Step 2 x^2 + 8x = 9 Step 3 ( x + 4 )^2 = 25 S

tep 4 x + 4 = 25 or x + 4 = - 25 Step 5 x = 21 or x = - 29. Where did Adele make her mistake. Show all of your work. ​

Mathematics
2 answers:
dusya [7]3 years ago
8 0
The mistake was in step one when she added the 9 to both sides

x^2 + 8x - 9 = 0
__ + __ = 8 (b)
__ • __ = -9 (a•c)
blanks = -1 and 9
(x - 1)(x + 9)
Solve for x in each one
x = 1 or -9
Dmitriy789 [7]3 years ago
4 0
<h3><em>The mistake was in step 1.  Here is how to correctly solve the equation: </em></h3><h3><em>x² - 8x – 33 = 0 </em></h3><h3><em>(x - 11) (x + 3) = 0 </em></h3><h3><em>x – 11 = 0 </em></h3><h3><em>x +3 = 0 </em></h3><h3><em>x = 11 and x = -3</em> </h3>

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Two fair number cubes are rolled. What is the probability the numbers are equal or the sum is odd?
Marat540 [252]

Answer:

0.6667 = 66.67%

Step-by-step explanation:

If each number cube has 6 numbers, the two cubes have a total of 6 * 6 = 36 results.

To have equal numbers in each cube, the cases are:

(1,1), (2,2), (3,3), (4,4), (5,5), (6,6) -> 6 cases

To have a odd sum, the cases are:

(1,2), (1,4), (1,6),

(2,1), (2,3), (2,5),

(3,2), (3,4), (3,6),

(4,1), (4,3), (4,5),

(5,2), (5,4), (5,6),

(6,1), (6,3), (6,5). -> 18 cases

So we have a total of 18 + 6 = 24 cases, then the probability is:

P = 24 / 36 = 0.6667 = 66.67%

5 0
3 years ago
Choose the explicit and recursive formulas for the geometric sequence 45, 135, 405, 1215, 3645, .... PLEASE HELP ASAP
sesenic [268]

Answer:

Option (B)

Step-by-step explanation:

Given sequence is 45, 135, 405, 1215, 3645..........

Since it's a geometric sequence,

Common ratio of each successive term to the previous term

r = \frac{135}{45}=3

First term of the sequence 'a' = 45

Explicit formula of a geometric sequence will be,

a_n=a(r)^{n-1}

a_n=45(3)^{n-1}

Recursive formula of this sequence will be,

a_n=3(a_{n-1}), a_1=45

Therefore, Option (B) will be the answer.

3 0
3 years ago
in a sale there is 25% off and a bed costs 33 pounds in the sale so how much was it before the sale ?
IceJOKER [234]
44 pounds 
gonna type so i can post this because of the 20 character limit :P
6 0
3 years ago
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lara31 [8.8K]

Answer:

80 sq.in

Step-by-step explanation:

One square's side = 4in

One square's area = 16 sq. in

16 x 5 = 80 sq.in

Hope that helps!

3 0
3 years ago
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1/2 is less than 1
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