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Algebra Videos 26 videos

SAT Math 1.5 Algebra and Functions
218 Views

SAT Math 1.5 Algebra and Functions. If f (x) = x2 - 16 and g(x) = x4 - 256, what is f of x divided by g of x?

ACT Math 1.5 Intermediate Algebra
386 Views

ACT Math Intermediate Algebra Drill 1, Problem 5. Can you simplify the expression?

ACT Math 2.1 Intermediate Algebra
359 Views

ACT Math Intermediate Algebra Drill 2, Problem 1. Solve the equation.

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SAT Math 8.3 Algebra and Functions 204 Views


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Description:

SAT Math 8.3 Algebra and Functions

Language:
English Language

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…

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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