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Passport to Advanced Math Videos 52 videos

Multiplying Polynomials to Find an Unknown Constant
3 Views

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

Recognizing Polynomial Factors
4 Views

When x = 12, a certain polynomial, y, equals 0. Which of the following must be true about the polynomial y?

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?

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SAT Math 9.4 Algebra and Functions 1300 Views


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Description:

SAT Math 9.4 Algebra and Functions

Language:
English Language

Transcript

00:02

Hope you left room for an extra helping of Shmoop.

00:05

If 3x squared + 5x = 12 and x is not an integer, then what must x be?

00:14

All right, so this question looks simple enough.

00:16

We have to find the solution to this equation where x ISN’T an integer.

00:20

So, first we can move 12 to the left side to get 3x squared + 5x – 12 = 0.

00:26

This format look familiar to ya?

00:28

Well, it really doesn’t look like we can factor this one, so let’s apply the quadratic formula.

00:35

So with 3 as a, 5 as b and negative 12, guest starring as c…we can now apply our formula.

00:42

Negative 5 plus or minus radical 25 plus negative 4 times 3 times negative 12…equals 144 all over 6.

00:50

…and 144 plus 25 is 169…ooh, magic number…

00:55

…so we have negative 5 plus or minus 13…all over 6.

01:00

Now we can just separate out the two plus or minus options…

01:04

…and we have negative 5 plus 13 over 6 and negative 5 minus 13 over 6.

01:11

The first one simplifies to 8 over 6, or just 4/3…

01:15

…and the second one simplifies to negative 18 over 6, or just negative 3.

01:19

So, since the question asks us for the non-integer solution to the equation,

01:24

we can forget about that last one.

01:26

Later, negative 3. So yeah…the answer is 4/3.

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