SOLUTION: Are the following functions linear, quadratic or neither of the two? Explain how you know. - y=3x-5 - y=(3x-2)(x+6)

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Question 254212: Are the following functions linear, quadratic or neither of the two? Explain how you know.
- y=3x-5
- y=(3x-2)(x+6)

Found 2 solutions by richwmiller, Edwin McCravy:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
first -linear no exponents
second quadratic- highest power 2 after foil

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!

"Linear" means that the largest exponent of x after the right side
is multiplied out and all like terms collected is 1.

"Quadratic" means that the largest exponent of x after the right side
is multiplied out and all like terms collected is 2.

"Cubic" means that the largest exponent of x after the right side
is multiplied out and all like terms collected is 3.

"Quartic" means that the largest exponent of x after the right side
is multiplied out and all like terms collected is 4.

"Quintic" means that the largest exponent of x after the right side
is multiplied out and all like terms collected is 5.

But right now you're only studying the first two, "linear" and "quadratic"

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y=3x-5

That doesn't need to be multiplied out or any terms collected.
And the largest power of x is 1, so it's linear.

-------------------------------

y=%283x-2%29%28x%2B6%29

That needs to be multiplied out and like terms collected:

y=%283x-2%29%28x%2B6%29

Use FOIL to multiply it out:

y=3x%5E2%2B18x-2x-12 

Collect like terms:

y+=+3x%5E2%2B16x-12

The largest power of x is 2, so it's quadratic.

[Note: You probably could just have looked at it and seen
that the largest power of x would end up being be 2 if you 
multiplied it out and collected like terms without actually
bothering to to do so.]

Edwin