Question

Solve this system of equations using the addition method?
x-y=6
-3y=x+22 Solve this system of equations using the addition method?
x-y=6
-3y=x+22 @Mathematics

Answer 1

y=-7 x=13

Answer 2

that true?

Answer 3

scale the 1st by -3

Answer 4

-3x +3y = -18
-3y = x+22
----------------
-3x = x+4

-4x = 4

Answer 5

how do you get x+4

Answer 6

by using the "addition" method ...

you add the 2 equations together after you modify one of them by a scalar

Answer 7

a scalar just means some number that you multiply the whole equation by to scale it up or down to something that you can use

Answer 8

o so i just substitute it

Answer 9

well, substitution will work as well; but this is a new method for you to learn so that you have many ways you can attack a problem to get to a solution

Answer 10

this "addition" method is also commonly refered to as "elimination" since the goal is to eliminate one of the variables

Answer 11

o ok thank you u make it sound easier to solve

Answer 12

so if i were to have -8x+3y=-5 and 8x-2y=6 i would add the _8x and the 8x to get zero then 3-2y to get y and -5+6 to get 1 right

Answer 13

practice helps :)

the steps are pretty much like this:


x - y = 6 ; (1)
-3y = x + 22 ; (2)

given 2 equations lets multiply one of them by a "n"umber to scale it. the easiest one would be the first one to me


n(x - y = 6) ; (1)
-3y = x + 22 ; (2)



nx - ny = 6n ; (1)
-3y = x + 22 ; (2)

now what does "n" have to be to get rid of the -3y? id say n = -3 will work



-3x - -3y = 6(-3) ; (1)
-3y = x + 22 ; (2)



-3x +3y = -18 ; (1)
-3y = x + 22 ; (2)

now we can add the equations together:



-3x +3y = -18 ; (1)
-3y = x + 22 ; (2)
----------------------

-3x = x + 4 ; (3)

and solve the new equation (3) for the remaining variable

Answer 14

if they give you:

-8x+3y =-5
8x-2y = 6

then yes the x parts are already set up for elimintion, just add the 2 equations together

Answer 15

ok thank u sooo much i would give u thousands of medals if i could

Answer 16

youre welcome, and good luck ;)