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2 years ago

Can someone please help me on 7

Mathematics

2 answers:

Korolek [52]2 years ago

8 0

Answer:

Step-by-step explanation:

plug in 5

5^2-5(4)+7=12

masya89 [10]2 years ago

4 0

<h3>Answer: B. f(x) = x^2-4x+7</h3>

===========================================

Work Shown:

f(x) = 3x-8

f(5) = 3*5-8 ... replace every x with 5; simplify with PEMDAS

f(5) = 15-8

f(5) = 7

We can cross choice A off the list since we got 7 as an output, instead of 12.

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f(x) = x^2-4x+7

f(5) = (5)^2-4(5)+7

f(5) = 25-4(5)+7

f(5) = 25-20+7

f(5) = 5+7

f(5) = 12

We got the output we wanted. So we can stop here.

---------------

If you're curious about the others, then,

f(x) = -x+14

f(5) = -5+14

f(5) = 9

That doesn't work, so we cross choice C off the list.

---------------

f(x) = |x-7|

f(5) = |5-7|

f(5) = |-2|

f(5) = 2

Choice D is crossed out as well.

So only choice B works.

You might be interested in

“I am thinking of a number such that 6 less than the product of 7 and this number is 85.”

Arada [10]

let x = the number

7x - 6 =85

add 6 to each side

7x =91

divide each side by 7

x = 91 /7 = 13

Answer is B 13

4 0

3 years ago

Read 2 more answers

It took sandy two hours to jog 13 miles. She ran 7 1/2 miles in one hour. How far did she run during the second hour

Zarrin [17]

Sandy ran 5 ½ during the second hour.

Total amount Sandy used to jog for 2 hours = 13 miles
Amount Sandy used to run in the 1st hour = 7 ½

<h2>Further Explanation</h2>

Therefore the amount Sandy used to run in the 2nd hour = Total amount Sandy used to jog for 2 hours – Amount Sandy used to run in the 1st hour

= 13 – 7 ½ (and can be expressed as 7 + ½)

= 13 – (7 + ½)

= 13 – 7 – ½

= 6 – ½ (otherwise expressed as 6/1 – 1/2)

= (6 x 2) – (1 x 1) / 2

= (12) – (1) / 2

= 12 – 1 / 2

= 11/2

= 5 ½

Hence, Sandy ran 5 ½ miles during the second hour.

Based on the above expression, it is observed that there is an element of fractions in the math problem. Also, BODMAS was clearly used to derive the solution to the given question.

Recall, 13 – (7 + ½). The mathematical signs, (–) and (+) were multiplied; one of mathematics rule states that – x + = –; thus 13 – 7 – ½

Notably, fractions deal with denominators and numerators; and in these questions, with the help of BODMAS, they (6/1 – 1/2) were used to factor each other out to derive the final answer 5 ½.

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