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
190 Views

SAT Math 1.3 Numbers and Operations. x and y must be which of the following?

SAT Math 2.4 Numbers and Operations
384 Views

SAT Math 2.4 Numbers and Operations

See All

SAT Math 3.5 Algebra and Functions 247 Views


Share It!


Description:

SAT Math 3.5 Algebra and Functions

Language:
English Language

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.

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
2779 Views

SAT Math 2.1 Geometry and Measurement. What is the measure of angle z in terms of x and y?

SAT Math 9.4 Algebra and Functions
1300 Views

SAT Math 9.4 Algebra and Functions

SAT Math 9.2 Algebra and Functions
377 Views

SAT Math 9.2 Algebra and Functions

SAT Math: Identifying an Equation for the Average of Two Percentages
23 Views

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...

SAT Math: Which Equation Represents Profit?
13 Views

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...