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3 years ago

2. Explain and correct the error made by a student who simplified this expression.

Mathematics

1 answer:

Ira Lisetskai [31]3 years ago

6 0

Answer:

what this student did was distribute the x to all 3 numbers when what they should have done was just combine 7x and -2x, and the answer should be 5x +8

Step-by-step explanation:

By the student placing x on the outside they are making the equation seem as if 8 also had an x. However if we look at the original problem 8 does not have any variable so right away that was their first mistake. Instead they had to find the numbers that had similar values. In this case it is negative 2x and 7x. We combine those two to get 5x+8 we cannot combine these two because as said previously 8 doesnt have a variable. so the answer stays with the expression 5x+8

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suppose 60% of kids who visit a doctor have a fever, and 20% of kids with a fever have sore throats. what's the probability that

kkurt [141]

Answer:

0.12

Step-by-step explanation:

Suppose there are 100 kids

60% have fever, so what is 60% of 100?

We convert percentage to decimal and multiply:

60/100 = 0.6

0.6 * 100 = 60 have fever

20% of the people having fever (60 of them) have sore throats, so,

What is 20% of 60?

We convert percentage to decimal and multiply:

20/100 = 0.2

0.2 * 60 = 12 have sore throat

So, how many people are there with fever AND sore throat, that is 12. We took initially there to be 100 people. Hence, the probability is:

$\frac{12}{100}=0.12$

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2 years ago

Number 53

Solnce55 [7]

X-intercepts
f(x) = 0

4x² - 15x - 4 = 0

4x² - 16x + x - 4 = 0

4x(x - 4) + 1(x - 4) = 0

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x = 4 or 4x = - 1 ⇒ x = - 1/4

Answer: -1/4 and 4.

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3 years ago

Bill went to the movies with some of his friends. tickets cost $8.50 each . they spent $18.00 total for food . their total was $

Marina86 [1]

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3 years ago

What is the mean of the values in the stem-and-leaf plot? Enter your answer in the box.

BartSMP [9]

Answer:

The mean is the average of a set of data.

Example:

To find the mean, add up all of the numbers in the set and divide by the number of values that you added.

35 + 36 + 37 + 38 + 40 + 40 + 41 + 42 + 43 + 55 + 55 + 55 + 56 + 57 + 58 + 59 = 747

Then, divide by the number of values, which is 16.

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Sergeeva-Olga [200]

$Other\ method:\\\\x;y-searches\\\\ \left\{\begin{array}{ccc}x+y=30&|subtract\ y\ from\ both\ sides\\x:y=3:2\end{array}\right\\\left\{\begin{array}{ccc}x=30-y&(1)\\\frac{x}{y}=\frac{3}{2}&(2)\end{array}\right\\\\subtitute\ (1)\ to\ (2):\\\\\frac{30-y}{y}=\frac{3}{2}\ \ \ \ |cross\ multiply\\\\(3)(y)=(2)(30-y)\\3y=60-2y\ \ \ \ |add\ 2y\ to\ both\ sides\\5y=60\ \ \ \ |divide\ both\ sides\ by\ 5\\\boxed{y=12}$

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3 years ago

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