ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Algebra II Videos 107 videos
Data doesn't do us much good if we can't interpret it. Ever snuck into a CPA's office while he slips out for a coffee break and tried to decipher o...
Statistics, Data, and Probability II Drill 4 Problem 2. Based on the graph, which statement is most likely to be supported by the data?
SAT Math 8.3 Algebra and Functions 204 Views
Share It!
Description:
SAT Math 8.3 Algebra and Functions
- Algebra and Functions / Systems of Linear Equations and Inequalities
- Product Type / SAT Math
- Algebra / Solve systems of equations
- Algebra / Solve systems of equations
- Algebra / Solve systems of equations
- Algebra / Solve systems of equations
- Heart of Algebra / Systems of linear equations in two variables (word problems)
Transcript
- 00:02
Here’s your shmoop du jour, brought to you by the difference of two squares.
- 00:06
Sure, all squares have their differences…but we hope these two can work things out.
- 00:12
If 9x2 - y2 = 15 and 3x - y = 3, what does 3x + y equal?
- 00:23
The most important thing is to recognize that, in this
- 00:25
problem, 9x squared minus y squared is a difference of two squares…
Full Transcript
- 00:33
…so “a squared minus b squared” can be factored into “a minus b times a plus b”.
- 00:41
9x squared is 3x times 3x.
- 00:43
So we can factor the first equation so it becomes (3x + y) times (3x - y) = 15.
- 00:50
Then we give a little whistle and call over the second equation…which we can now substitute:
- 00:55
(3x + y) times 3 = 15; then, dividing both sides by 3, we get 3x + y = 5.
- 01:01
So our correct answer is 5. Good boy. Now…roll over.
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...