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SAT Math 9.2 Algebra and Functions
377 Views

SAT Math 9.2 Algebra and Functions

SAT Math 9.4 Algebra and Functions
1300 Views

SAT Math 9.4 Algebra and Functions

Multiplying Polynomials to Find an Unknown Constant
3 Views

In the equation above, if a, b, and c are all constants, what is c?

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SAT Math 9.6 Algebra and Functions 275 Views


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SAT Math 9.6 Algebra and Functions

Language:
English Language

Transcript

00:03

Here’s your shmoop du jour, brought to you by Absolute Value.

00:07

Putting the “abs” in “absolute.”

00:10

| 3x squared + 2x | = 8

00:15

What is the largest possible value for x?

00:20

Okay, so…while x may be equal to more than one value, the only correct answer is the largest.

00:26

Let’s keep that in mind. First, remember that,

00:29

when solving absolute value equations, we split them into the two possibilities.

00:33

The number under the absolute value is either positive or negative 8.

00:37

Let’s start with 3x squared + 2x = 8. We subtract 8 from both sides, and get 3x squared + 2x – 8 = 0.

00:46

Then, it’s just a simple matter of using the quadratic formula.

00:49

Plugging in our values and solving...

00:57

...we get that x can be either 4/3, or -2.

01:01

Remember we want the largest, so -2 is out.

01:05

The other equation is 3x squared + 2x = -8.

01:09

We add 8 to both sides to get our quadratic.

01:12

Then, we use the quadratic formula again to find x.

01:16

But when we actually try to plug our numbers into the quadratic formula, we see that we’re

01:20

trying to take the square root of -92.

01:23

Uh, good luck with that. Turns out there is no real solution to this equation.

01:27

And since there are no real solutions… the only possible answers

01:30

come from solving 3x squared + 2x = 8.

01:33

So our answer is 4/3.

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