Given the function f(x) = 3x2 − 4, what is f(-2)? A. -40 B. -16 C. 8 D. 32
2 answers:
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Answer: 1/10 miles/hour
To find how fast a snail moves in miles per hour, we can find the unit rate using a proportion.
<h2>Unit Rate</h2>The unit rate is the amount per one unit. In this problem, the unit is for one hour. One way to find the unit rate is by using a proportion.
<h2>Proportions</h2>Proportions look like two fractions set equal to each other with a missing variable to solve.
<h3>State our variables</h3>let <em>x</em> be the number of miles per hour
<h3>Write a proportion</h3>The first fraction has a number for the numerator (top) and denominator (bottom), because the question gives us the information. The second fraction has a missing value, <em>x</em>, that we are solving for. We can write <em>x</em> in the numerator.
We can solve by finding the scale factor. The scale factor is the number we can multiply the numerator by to find <em>x</em>.
<h3>Find the scale factor</h3>Start with the proportion.
To find the scale factor,
- Take the denominator from the fraction with a variable:
- Take the denominator from the fraction that has no variable:
- Divide step 1 by step 2 and solve:
Our scale factor is <u>3</u>.
<h3>Solve for x</h3>We can find <em>x</em> by multiplying the numerator in the first fraction by the scale factor. This is because <em>x</em> is also in the numerator.
Simplify 3/30 by dividing the fraction by 3.
x = 1/10
∴ a snail moves 1/10 miles per hour.
Learn another way to solve proportions here: brainly.com/question/18437927