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Systems of Linear Equations and Inequalities Videos 9 videos
SAT Math 1.1 Algebra and Functions. Find an algebraic equation to correspond with the data.
SAT Math 1.3 Algebra and Functions. How many 16 oz. bottles did she buy?
SAT Math 8.3 Algebra and Functions 204 Views
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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.
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