Question

using y=5x+70 and y=5x+80 form a system of two linear equations in two variables.

Answer 1

@skullpatrol

Answer 2

solve one of the equations for x, then plug your answer into the x value on the other equation and solve for Y

Answer 3

try bring the 80 to the other side of the = and the making x by itself. then use what x= in that equation and put it into the other one

Answer 4

so if i bring the 80 over it would be y-80=5x

Answer 5

yupp, and since both equations have a "5x" in them, you can replace the "5x" in the other formula and solve for y

Answer 6

ok so it would be y=(y-80)+70

Answer 7

but then wouldn't my y's cancel out

Answer 8

you have to solve the other equation for 5x as well before you substitute

Answer 9

\[5x=y-80\] and \[5x=y-70\]

Answer 10

so y-80=5x
and y-70=5x

Answer 11

then what

Answer 12

the replace one of the 5x with the equation for the other

Answer 13

no sorry wrong, been a while since i did this. you have to add the two equations first

Answer 14

?

Answer 15

ok so

Answer 16

\[0=5x+10-y\]

Answer 17

70 not 10

Answer 18

ok

Answer 19

the the other one would be 0=5x+80-y?

Answer 20

and then plug in for y because its easier. so you get
\[0=5x+70-(5x+80)\]

Answer 21

and you solve for x

Answer 22

but then the x cancels out?

Answer 23

disregard those lines are linear

Answer 24

So what does that mean?

Answer 25

im supposed to sole the systems using any method we want.

Answer 26

they are parallel, the question has no answer in the form ax+by=p, cx+dy=q the way a normal linear system would

Answer 27

http://tutorial.math.lamar.edu/Classes/Alg/SystemsTwoVrble.aspx

Answer 28

isn't it y=mx+b

Answer 29

no

Answer 30

that the form of the lines i have?

Answer 31

they want you to prove that these equations are parallel

Answer 32

so you have to set them equal,
\[5x+70=5x+80\]
then the 5x cancel out and you are left with
70=80
which we know is not true therefore the two lines never cross and are parallel

Answer 33

does that make sense to you?

Answer 34

yup

Answer 35

glad I was able to help :)