ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Math Videos 320 videos
SAT Math 1.3 Numbers and Operations. x and y must be which of the following?
SAT Math 3.5 Algebra and Functions 248 Views
Share It!
Description:
SAT Math 3.5 Algebra and Functions
SAT Math 3.5 Algebra and Functions
Transcript
- 00:04
It's a bird! It's a plane! It's Shmooperman!
- 00:09
If y equals 2x + z over z + 1, what happens to the value of x when y and z are doubled?
- 00:16
And here are the potential answers…
- 00:21
There are three variables, and the question asks what happens to one of them,
- 00:24
x, if we change the other two, y and z.
Full Transcript
- 00:29
Well, first we should isolate x so that we can see what happens.
- 00:32
First, we multiply both sides by z + 1, and get y times z + 1 is equal to 2x + z
- 00:40
Next, we subtract z from both sides so that we can further isolate x.
- 00:44
Finally, we divide both sides by 2, and x is fully isolated.
- 00:49
At this point we can plug in test values.
- 00:52
An easy value is always 1. We can plug in 1 for both y and z.
- 00:56
And we'll see that x is equal to 1/2.
- 01:00
What happens when y and z are doubled?
- 01:02
Well, if we plug in y and z equal 2, we'll get x equals 2 as our answer.
- 01:09
2 is four times bigger than 1/2 and looks like D is our answer. Done.
Related Videos
SAT Math 2.1 Geometry and Measurement. What is the measure of angle z in terms of x and y?
In 2014, the unemployment rate of one county in California was 7%. In another county, the unemployment rate was 11%. Which of the following express...
Angela is making cookies for a bake sale. She expects each batch of her cookies to sell for $40. It costs her $10 to make one batch of cookies, and...