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3 years ago

Carly solved a quadratic equation by completing the square, but her work has errors. Identify the first error in Carly's work.

Mathematics

1 answer:

Savatey [412]3 years ago

8 0

Answer:

Her first error was adding the wrong number to both sides. Instead of 4², it should be 2²

Step-by-step explanation:

When completing the square, the number that needs to be added to both sides is (b/2)²

In this problem, b is 4. So, Carly should have added 2² to both sides, but she added 4² instead.

So, her first error was adding 4² to both sides instead of 2²

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2 years ago

Subtract -5x²+10x-1from6x²-x+3

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2 years ago

A student needs to select 3 books from 3 different mathematics, 3 different physics and 1 history books. What is the probability

Gnesinka [82]

Answer:

Probability that one of them is mathematics and other two are either physics or history books = 0.51

Step-by-step explanation:

Given - A student needs to select 3 books from 3 different mathematics, 3 different physics and 1 history books.

To find - What is the probability one of them is mathematics and other two are either physics or history books ?

Solution -

Given that,

A student needs to select 3 books from 3 different mathematics, 3 different physics and 1 history books.

So,

Total number of books = 3 + 3 + 1 = 7

The student has to select 3 books

So, Total number of ways = $^{7} C_{3}$ = 35

So,

Probability that one of them is mathematics and other two are either physics or history books is -

= $\frac{^{3} C_{1}. ^{4} C_{2} }{^{7} C_{3}}$

= $\frac{(3)(6)}{35}$

= $\frac{18}{35}$

= 0.51

⇒Probability that one of them is mathematics and other two are either physics or history books = 0.51

8 0

2 years ago

Sara ordered 2 slices of pizza and a 12-ounce cola and paid

Natasha_Volkova [10]

Answer: a slice of pizza cost $1.25 and a 12-ounce cola cost $0.50.

Step-by-step explanation:

Let slice of pizza cost x and a 12-ounce cola cost y.

Then Sara's order cost: 2x+y=3

and Sydney's order cost: 3x+2y=4.75

From the first equation we have: y=3-2x and put this to the second equation:

3x+2(3-2x)=4.75

3x+6-4x=4.75

x=1.25

y=3-1.25*2=0.50

Answer: a slice of pizza cost $1.25 and a 12-ounce cola cost $0.50.

5 0

3 years ago