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2 years ago

What method would you choose to solve the equation 2x2 – 7 = 9? Explain why you chose this method.

2 answers:

8 0

Sample Response/Explanation: I would use the square root property of equality. Because there is no x term, I would just add and divide to get x2 by itself. Then I would take the square root.

oksano4ka [1.4K]2 years ago

7 0

I would add 7 to get ...

... 2x² = 16

then divide by 2 to get

... x² = 8

Now, I would take the square root, recognizing that both positive and negative values will solve the problem.

... x = ±√8

The root can be simplified, so we have ...

... x = ±2√2

_____

The above method seemed the most obvious method to me. One could use the quadratic formula, but that seems to involve more operations.

... 2x² -16 = 0 . . . . subtract 9

... x = (-0 ± √(0² -4·2·(-16)))/(2·2) . . . . put the coefficients into the formula

... x = ±(√128)/4 = ±√8 = ±2√2 . . . . . simplify the result

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Three friends are playing catch. Zoe is in a straight path 12 feet to the west of alex. Jin is in a straight path 9feet to the n

Tanzania [10]

Answer:

15 ft

Step-by-step explanation:

This problem can be represented by a right angle triangle, shown in the diagram below.

The distance between Jin and Zoe is the hypotenuse of the triangle, x.

According to Pythagoras theorem,

hyp² = opp² + adj²

Where opp is the opposite side and adjacent is the adjacent side to any angle of consideration (which is not important in this case)

Hence:

x² = 12² + 9²

x² = 144 + 81

x² = 225

Finding the square root:

x = 15 ft

Jin and Zoe are 15 ft apart.

4 0

2 years ago

Jackson buys a grape snow cone on a hot day. By the time he eats all the "snow" off the top, the paper cone is filled with 27\pi

anyanavicka [17]

Question:

Jackson buys a grape snow cone on a hot day. By the time he eats all the "snow" off the top, the paper cone is filled with 27\pi27π27, pi cm^3 3 start superscript, 3, end superscript of melted purple liquid. The radius of the cone is 333 cm. What is the height of the cone?

Answer:

The height of the cone is $9 \ cm$

Explanation:

It is given that the radius of the cone is $3 \ cm$

The volume of the cone is $27\pi$

The height of the cone can be determine using the formula,

$V=\frac{1}{3} \pi r^{2} h$

Substituting the values $V=27 \pi$ and $r=3$ , we get,

$27 \pi=\frac{1}{3} \pi(3)^{2} h$

Multiplying both sides by 3, we have,

$81 \pi= 9\pi h$

Dividing both sides by $9 \pi$ , we have,

$9=h$

Thus, the height of the cone is $9 \ cm$

4 0

2 years ago

Jamal works in a city and sometimes takes a taxi to work. The taxicabs charge $1.50 for the first 1/5 mile and $0.25 for each ad

Natalija [7]

1.50+.25x=3.75
.25x=2.25
x=9
9/5+1/5=10/5
2 miles

4 0

2 years ago

Read 2 more answers

Select all of the following true statements if R = real numbers, Z = integers, and W = {0, 1, 2, ...}.

PSYCHO15rus [73]

We can start solving this problem by first identifying what the elements of the sets really are.

R is composed of real numbers. This means that all numbers, whether rational or not, are included in this set.

Z is composed of integers. Integers include all negative and positive numbers as well as zero (it is essentially a set of whole numbers as well as their negated values).

W on the other hand has 0,1,2, and onward as its elements. These numbers are known as whole numbers.

W ⊂ Z: TRUE. As mentioned earlier, Z includes all whole numbers thus W is a subset of it.

R ⊂ W: FALSE. Not all real numbers are whole numbers. Whole numbers must be rational and expressed without fractions. Some real numbers do not meet this criteria.

0 ∈ Z: TRUE. Zero is indeed an integer thus it is an element of Z.

∅ ⊂ R: TRUE. A null set is a subset of R, and in fact every set in general. There are no elements in a null set thus making it automatically a subset of any non-empty set by definition (since NONE of its elements are <u>not</u> an element of R).

{0,1,2,...} ⊆ W: TRUE. The set on the left is exactly what is defined on the problem statement for W. (The bar below the subset symbol just means that the subset is not strict, therefore the set on the left can be <u>equal</u> to the set on the right. Without it, the statement would be false since a strict subset requires that the two sets should not be equal).

-2 ∈ W: FALSE. W is just composed of whole numbers and not of its negated counterparts.

3 0

2 years ago

Read 2 more answers

Which statements are true about David's work? Check all that apply. The GCF of the coefficients is correct. The GCF of the varia

Anon25 [30]

Answer:

The GCF of the coefficients is correct.

The variable c is not common to all terms, so a power of c should not have been factored out.

In step 6, David applied the distributive property.

Step-by-step explanation:

Given the polynomial :

80b⁴ – 32b²c³ + 48b⁴c

The Greatest Common Factor (GCF) of the coefficients:

80, 32, 48

Factors of :

80 : 1, 2, 4, 5, 8, 10, 16, 20, 40, and 80

32 : 1, 2, 4, 8, 16, and 32

48 : 1, 2, 3, 4, 6, 8, 12, 16, 24, and 48.

GCF = 16

b⁴, b², b⁴

b⁴ = b * b * b * b

b² = b * b

b⁴ = b * b * b * b

GCF = b*b = b²

GCF of c³ and c

c³ = c * c * c

c = c

GCF = c

We can see that David's GCF of the coefficients are all correct

From the polynomial ; 80b⁴ does not contain c ; so factoring out c is incorrect

In step 6 ; the distributive property was used to obtain ; 16b²c(5b² – 2c² + 3b²)

6 0

1 year ago

Read 2 more answers