I'll go over part A.
What's happening is that we are plugging some unknown number x into the function, and getting -1 as the result. The function rule is 3*x-7 which translates to "multiply the input number by 3, then subtract off 7"
Notice how multiplication comes first and then we subtract. This is following the order of operations PEMDAS (some books may call it BEDMAS depending on your region). The M for multiplication comes before the S for subtraction.
To isolate x, we follow the order of operations in reverse. We undo the "subtract off 7" then we undo the "multiply by 3"
So this is how it all works out
f(x) = 3x-7
-1 = 3x-7 .... replace f(x) with -1
3x-7 = -1
3x-7+7 = -1+7 ... add 7 to both sides to undo the "-7"
3x = 6
3x/3 = 6/3 ... divide both sides by 3 to undo the "multiplication"
x = 2
Therefore, if the input is 2, then output is -1
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Let's plug x = 2 into the function and see what happens
f(x) = 3x-7
f(2) = 3*2-7 .... replace x with 2
f(2) = 6-7 .... multiply
f(2) = -1 .... subtract
The input x = 2 leads to the output -1
So this confirms that x = 2 is the proper answer for part A
The ordered pair that would represent a ratio that is equivalent to those shown is (8, 12)
<h3>Ratio and proportions</h3>
From the given diagram, we can create two coordinate points which are (2, 3) and (4, 6)
We need to determine the ordered pair would represent a ratio that is equivalent.
Multiplying the coordinate by a scale factor of 4 will give
A(2, 3) = A'(4(2), 4(3)) = (8, 12)
Hence the ordered pair that would represent a ratio that is equivalent to those shown is (8, 12)
Learn more on coordinate pair here: brainly.com/question/1528681
I guess your question is
<span>Sean read 15 of a book in 112 hours. How long will it take Sean to read 12 of this book?
15 books ........112 hours
12 books..........? hours
12 x 112 / 15 = 89.6 hours.
</span>
1. 5/16
2. 1/3
3. 3/20
4. 38
5. 3/4
6. 6
Area of semicircle = 1/2 x pi x radius x radius
radius of semicircle = 14/2 = 7
pi = 3.14 for this question, so
1/2 x 3.14 x 7 x 7 = 76.93
area = 76.93
