Question

Help with functions:

Answer 1

linear function is a straight line or has constant change

which function when graphed looks like a straight line?

Answer 2

linear means "line". like in y= mx +b

if you see exponents or powers or square roots it Is NOT linear

if the graph is a perfectly STRAIGHT LINE, it is linear
otherwise, it is not

Answer 3

well its not b definetly
for this problem can we use y=mx+b

Answer 4

so its not c its betwween a and d

Answer 5

D also has an exponent.

Answer 6

no d has an expnent

Answer 7

its a

Answer 8

can you help me with another question

Answer 9

yes, it is (a).

you could (if you wanted to) figure out the equation y = mx +b
by finding the slope (change in y divided by change in x)
use any two pairs of numbers. But it is linear (by process of elimination we found that out)

Answer 10

okay ur the best :)

Answer 11

now can u help me with another question?

Answer 12

Part A asks for which equation? there are lots and lots of equations she could write down, unless you have to pick from a list...

Answer 13

I would change
10x + 5y =20
to y = mx +b format

add -10x to both sides
10x - 10x + 5y = -10x+20
or 5y = -10x+20
divide both sides (all terms) by 5

y= -2x +4

-2 is the slope. write down an equation of a line with a different slope, and it is bound to intersect this line somewheres. where the lines meet is the "solution" of the two equations

Answer 14

so should i write down y=-2x+4 as my answer for part a ?

Answer 15

y=-2x+4 is another way to write 20+5y=20
It is the exact same line (written in slope-intercept form)
the exactly same line, if you plot it twice, will line on top of itself. It will "meet" the first line everywhere. You want a line that crosses only once.

Answer 16

so that the answer right?

Answer 17

I guess you are not reading what I posted. Read the 2 posts again, carefully

Answer 18

okay i knida of understand so its not y=-2x+4

Answer 19

can it something perpendicular to that line

Answer 20

Here is the idea:

plot a line (the one they gave you)

plot another line. If they cross, they cross exactly once, and where they meet is the "solution"

Answer 21

Here is a case where the two lines *never cross*

Answer 22

If you look at the equation of both lines you can tell if they will cross or not. How?
look at the slope (the number in front of the x *if the equation is in slope intercept form*
IF THE SLOPES ARE DIFFERENT, THE LINES MEET and give ONE SOLUTION.

y= -2x +4 is the equation of the line they gave you

the number in front of the x is -2

if you write down another equation, and change the -2 to something else, that line will cross the first line.

Answer 23

so y=-2x+6 ?

Answer 24

can that work?

Answer 25

Do you see you can pick lots of equations that will cross (there are lots of numbers different from -2)

so y=-2x+6 ?

what is the slope of that line ? Is the slope DIFFERENT from -2 ?

Answer 26

are you trying to tell me that theyshould have the same slope but difrent y intercepts?

Answer 27

the slope of the line is -2 and no its not diffrent

Answer 28

are you trying to tell me that theyshould have the same slope but difrent y intercepts?

If they did the lines would be parallel, going in the same direction, never getting closer.
That is the case of NO SOLUTION

Answer 29

so y=-2x+6 is the answer to part a right ?

Answer 30

or part b ? im getting confused :)

Answer 31

for part (a), remember this

IF THE SLOPES ARE DIFFERENT, THE LINES MEET and give ONE SOLUTION.

Answer 32

so can I put something like y= 1/2x+4

Answer 33

part (a) wants one solution. It wants the lines to meet. It wants the lines to have different slopes

Answer 34

so can I put something like y= 1/2x+4

yes, *anything* except -2 in front of the x

Answer 35

okay i understand what about part b?

Answer 36

part b wants something thatll give you infinte solutions

Answer 37

for two lines to meet everywhere, they have to be the same line.

you need to write down the *same line*
10x + 5y =20

but you can disguise it. Divide all the terms on both sides by 5.
it will be the same line, but look different

Answer 38

what do you mean jsut put y=-2x+4 as my answer ?