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Systems of Equations Videos 73 videos
CAHSEE Algebra I: Drill 1, Problem 1. What are some of the properties used to solve this equation?
Algebra I Drill 2, Problem 3. Which of the following is the same as the expression?
CAHSEE Math 5.2 Mathematical Reasoning 177 Views
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Description:
Mathematical Reasoning Drill 5, Problem 2. Which of the following represents the relationship between x and y?
Transcript
- 00:03
Here’s an unshmoopy question you’ll find on an exam somewhere in life.
- 00:07
The following set of coordinate points consists of the values of x and the corresponding values of y.
- 00:14
{(0, 5), (1, 3), (2, 1), (3, -1)}.
- 00:17
Which of the following represents the relationship between x and y?
- 00:21
And here are the options…
Full Transcript
- 00:26
It’s plug’n’chug time.
- 00:27
One of the equations will satisfy ALL of the given coordinate points.
- 00:31
We just have to do some detective work and find which one it is.
- 00:34
Let's start with A… the given equation is y equals x plus 5.
- 00:39
Does that satisfy the coordinate (0, 5)?
- 00:42
Well, if we plug in 0 for x and 5 for y: 5 = 0 + 5.
- 00:47
So far so good. How about the second coordinate, (1, 3)?
- 00:51
Let’s try it out: 3 = 1 + 5.
- 00:56
Hmm, only in an Orwellian negative utopia does 1 plus 5 equal 3.
- 01:01
We can scrap A. Moving on to option B… y equals 2x plus 1.
- 01:06
Plug in the first coordinate: 5 = 2(0) + 1.
- 01:10
Nope, 5 does not equal 0 + 1. We can say goodbye to B.
- 01:14
Option C is y equals 2x minus 3. Let’s plug in (0,5).
- 01:19
Does 5 equal 2(0) – 3? No, 5 does not equal negative three.
- 01:26
Last chance, so let’s make it a good one… option D.
- 01:29
The equation is y equals negative 2x plus 5.
- 01:34
Plug in (0,5): 5 equals negative 2 times 0 plus 5. 5 does equal 0 plus 5.
- 01:43
Let’s try the second coordinate: (1,3). Is 3 equal to negative 2 times 1 plus 5?
- 01:49
Yup, 3 equals -2 plus 5. We’re on a roll!
- 01:56
Just to be sure, we’re going to plug the last two coordinates into the equation.
- 02:00
Is 1 equal to negative two times 2 plus 5? Yup, negative 4 plus 5 equals 1.
- 02:08
And the last one… is negative 1 equal to negative 2 times 3 plus 5?
- 02:14
Yeah, negative 1 equals negative 6 plus 5.
- 02:17
D satisfies all of the coordinates.
- 02:19
As in, “Detective Retirement Community.”
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