Question

does anyone know how to solve using equivalent equation/expression? im doing a unit solving systems (algebra) my question is -2x+y=8 and theres another equation to this same problem which is 3x+2y=9 i also have to solve using graphs and by substitutions

Answer 1

solve either of the equations for x or y

Answer 2

thanks but also when i was done i got y=8=2x

Answer 3

just solve one for either x or y

Answer 4

oh ,lol im slow haha thanks

Answer 5

No my first sentence was too ambiguous

Answer 6

Need any more help?

Answer 7

oh its ok and how would i solve it for graphs?

Answer 8

Well I am not sure exactly what they want

Answer 9

they want me to graph what i got for the equation

Answer 10

What did you get for the equation? I think maybe they want you to add the equations and graph the answer

Answer 11

i got 2x+8=y
and y=4.5-1.5x so would i set them equal to eac other to get the eqation for the graph?

Answer 12

I am not sure. If you set the two equal to each other that would be finding the point at which the two functions intersect

Answer 13

hmm yeah you right

Answer 14

Do you have the original question?

Answer 15

yes

Answer 16

If you are trying to solve this system of equations then you only need to know the point at which the two graphs intersect because that point gives one x and one y such that both equations are true

Answer 17

-2x+y=8}
3x+2y=9 }
solve by graphing question a
solve by using equivelent equations/expressions question 2
yes but how do i get it?

Answer 18

So, we need to set the two functions equal and to make it easier on our selves lets solve both for y

Answer 19

ok(:

Answer 20

so for the first i got y=8+2x

Answer 21

y = (9-3x)/2 and y = 8 + 2x Nice job

So for what x is 8 + 2x = (9-3x)/2?

Answer 22

and the second y=4.5-1.5

Answer 23

thank you

Answer 24

totally, I wrote mine a little differently but they are equvalent

Answer 25

Well, we just need to solve for x!

Answer 26

thankyou so much!

Answer 27

Did you get a value for x yet?

Answer 28

almost

Answer 29

i got- 7

Answer 30

8 + 2x = (9-3x)/2

Multiply both sides by 2: 2(8 + 2x) = 9-3x, 16 + 4x = 9 - 3x

Add 3x to both sides: 16 + 7x = 9

Subtract 16 from both sides: 7x = -7

Divide both sides by 7: x = -1

Maybe check your multiplication and addition on that one

Answer 31

Now we only need our y coordinate

Answer 32

so 8+2(-1)=6 so(-1,6)?

Answer 33

So I am going to pick one of the equations and substitute x = -1 in

y = 8 + 2(-1)

y = 8 -2

y = 6

So now we have our solution kind of by graphing. We found the point at which the two equations intersect and you are correct it is (-1,6)

Answer 34

Good luck, keep up the good work

Answer 35

ok so i put the point on the graph at (-1,6)

Answer 36

thank you

Answer 37

Oh I'm sorry is there something else you needed with?

Answer 38

oh it just that what do i do to plot the other points?

Answer 39

The two equations or functions whatever you want to call them

y= 4.5 - 1.5x and y = 8 + 2x

The y-intercept of the first I am going to call the first function f(x) so as not to get confused
is 4.5 and the slope of f(x) is -1.5

The y-intercept of the second which ill call g(x) is 8 and its slope in 2

Answer 40

so i would so two down and two pos. (right) in a linear function

Answer 41

two up and two right

Answer 42

ok thank you so much for you time i really appreciate it thank you(:

Answer 43

No problem it was fun

Answer 44

(: