ShmoopTube

Where Monty Python meets your 10th grade teacher.

Search Thousands of Shmoop Videos


Problem Solving and Data Analysis Videos 50 videos

Using Conversion Factors to Solve for Density in Moles
8 Views

A mole is a unit used in chemistry to measure atoms, molecules, electrons, and other particles in a given amount of substance. We know that the mol...

Identifying Exponential Patterns in a Data Set
4 Views

The table above estimates the population increase of a colony of bacteria over the course of five years. Which of the following best characterizes...

Calculating Probability Using Watermelon Candy and Email Surveys
3 Views

Employees of a candy company surveyed people of different ages and asked them their favorite flavor of candy. One of the surveyors chooses to send...

See All

SAT Math 9.3 Algebra and Functions 225 Views


Share It!


Description:

SAT Math 9.3 Algebra and Functions

Language:
English Language

Transcript

00:05

The line y = -2x + 4 is reflected over the y-axis, then translated up three units and left two units.

00:12

What is its new y-intercept?

00:17

There are two ways to do this problem: algebraically and graphically.

00:24

Let’s start with “algebraically.”

00:26

We’re given a line and a series of transformations, so we’ll apply them to the equation of the line.

00:32

First is a reflection over the y-axis. That means we have to change x into negative x.

00:38

Our line changes to y = 2x + 4. Next up is a “3 unit up” translation.

00:45

For this, we just… add 3 to the line. We get y = 2x + 7.

00:50

Finally, we have a left shift of 2.

00:53

To apply this one, add 2 to x.

00:56

To get this equation back into slope intercept form, we distribute the 2 into the parentheses

01:00

and get y = 2x + 11.

01:03

Remember that the y intercept of a line in slope intercept form is just the constant

01:07

added onto the end.

01:09

In this case… 11. That's our y intercept.

01:13

Another way to solve this problem is graphically.

01:15

We start with the graph of y = -2x + 4

01:20

First, we have the reflection across the y-axis.

01:23

Then we move it up 3.

01:25

Finally, we shift the graph 2 to the left.

01:28

By looking at the graph, we can also see that the y intercept is 11.

01:33

Booyah. Two paths – same destination.

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...