Question

Determine whether the function is linear or quadratic. Identify the quadratic, linear, and constant terms.

y= (x-5)(5x+4)-5x^2

A.linear function
linear term: 15x
constant term: –25

B.quadratic function
quadratic term: 5x^2
linear term: 15x
constant term: –25

C.linear function
linear term: -21x
constant term: –20

D.quadratic function
quadratic term: -5x^2
linear term: -21x
constant term: –20

Answer 1

Just multiply it out!
\[y= (x-5)(5x+4)-5x^2\]
\[(x-5)(5x+4) = ?\]

Answer 2

5x^2 -21x - 20 @austinL

Answer 3

Correct. So now we have
\[(5x^2 -21x - 20)-5x^2\]

Answer 4

what would I do from here?

Answer 5

@austinL

Answer 6

You just simplify.
You have only two terms with a factor of 2 so
\[5x^2−21x−20−5x^2=5x^2−5x^2−21x−20\]

Answer 7

I got -21x-20 = -21x-20

Answer 8

@austinL

Answer 9

Now is that one of your answers? *hint, it is* *cough, cough C, cough*

Answer 10

hahah Thanks man.

Answer 11

Yep, no problem!

Answer 12

@austinL can you help me with one more its easy

Answer 13

Sure, I can try.

Answer 14

Identify the vertex and the y-intercept of the graph of the function y= -3(x+2)^2+5

A.vertex: (2, -5); y-intercept: -12
B.vertex: (-2, -5); y-intercept: 9
C.vertex: (-2, 5); y-intercept: -7
D.vertex: (2, 5); y-intercept: -7

Answer 15

@austinL

Answer 16

(x+2)(x+2)=?

Answer 17

x^2 + 4x+4

Answer 18

Correct, now multiply that all by 3.

Answer 19

3x + 12x + 12

Answer 20

now add 5 to that.

Answer 21

to all of it?

Answer 22

No, just to the terms without a variable. :)

Answer 23

3x+ 12x + 17

Answer 24

Wait, rewind. Multiply it by (-3) sorry.

Answer 25

-3x-12x-17

Answer 26

then add 5 to that :D

Answer 27

-3x-12x-12

Answer 28

\[3x^2-12x-12\]. So now what is your y intercept?

Answer 29

-12

Answer 30

Right, is that in one of your answers?

Answer 31

yes for A.

Answer 32

there you go!

Answer 33

thank you

Answer 34

No problem!