Question

Part 1: Decide whether you would use the graphing, substitution, or elimination method to solve the following system of equations. Explain, in complete sentences, why you chose that method.
Part 2: Solve the following system of equations and show all of your work.

5x + 3y = 8
y = −2x + 1

Answer 1

i know how to do elimination and substitution but not fully

Answer 2

@uri

Answer 3

no

Answer 4

help @tcarroll010

Answer 5

Choosing substitution as your choice for solving is the right way to go here because that second equation is already in a form that specifies the variable because you have:

y equals "something on the right"

You can take that "something on the right" from equation #2 and put that in the first equation wherever you have "y". That way you can solve equation #1 as it will now be in only one variable, "x".

Answer 6

ok so it would be 3y=8-5x for the first part which equals y?

Answer 7

and then u plug that into the equation?

Answer 8

?

Answer 9

equation #2

Answer 10

yes. so then the equation would be 8-5x −2x + 1??

Answer 11

or 3(8-5x) −2x + 1??

Answer 12

You're not following the steps I outlined. What does y equal from equation #2?

Answer 13

y=-2x+1

Answer 14

im not really good at this sorry

Answer 15

The equations have a left side and a right side. I said to take that right side of equation #2 and put that (just the right side, because that is another form of "y") into equation #1 where you see the "y".

Answer 16

oh ok so its 5x + 3(-2x+1) = 8

Answer 17

Yes, now you're getting it! That's the "substitution" concept. Now you just simplify that and solve for "x". When you get "x", you can go back to either ORIGINAL equation, put that "x" in, and solve for "y".

Answer 18

oh ok so when i simplify it it would be

5x + 3 (-2x+1)=8
5x -6x + 3 = 8
-1x + 3= 8
- 3 - 3
-1x = 5
x = -5

Answer 19

Yes, that's "x", so just solve for "y" now, using what I pointed out.

Answer 20

and then 5 (-5) + 3y = 8
-10 + 3y = 8
+10 +10
3y = 18
3y/3 = 18/3
y = 6

Answer 21

5(-5) is not -10

Answer 22

so y = 11

Answer 23

sorry i wasnt thinkinh

Answer 24

Yes, you got it right, good job!

Answer 25

All good now, @awk0perf ?

Answer 26

yes ty

Answer 27

uw! Nice working with you!

Answer 28

thanks