Hello! I need help in math, solving system of equations by substitiution. The problem is X+Y=3 and X=2Y.?

Question

Can anyone show me how to work this problem step by step?

Answer 1

Replace x with 2y

2y + y = 3

3y = 3

y = 1

Replace y with 1

x + 1 = 3

x = 2

(2, 1) is the solution

Answer 2

x + 2y = 4 x – y = 3 x = y + 3 Now plug y + 3 in as x into the different equasion: (y + 3) + 2y = 4 3y + 3 = 4 3y = a million y = a million/3 Now plug a million/3 in as y back into the 1st one to discover x: x - a million/3 = 3 x = 4/3 So the respond is (4/3, a million/3) on a coordinate airplane.

Answer 3

So you have the problem x+y=3 and x=2y. The first step is to take the second equation x=2y, and put it in, or substitute it for the x in the first equation so it will look like (2y)+y=3. Then you add like terms so it looks like 3y=3. Then divide both sides by three and you have y=1. Then you take your y answer and put it back into the first equation so it looks like x+1=3. Then from there you subtract 1 on both sides and that will give you your x value.

Answer 4

ok. this is a very simple problem and i am going to show you, ok? first off the equations are:

X + Y = 3
X = 2Y

now since X = 2Y what you do is substitute the x in X + Y = 3 for 2Y so the equation will look like:
2Y + Y = 3
now all you do is solve for Y:
so
3Y = 3
then what you do is isolate the Y by diving both sides by 3 which will look like this:
3/3 Y = 3/3

which turns out to be
Y = 1
so now that you know what Y equals to you can solve the other equation which is:
X = 2Y
since Y=1 substitue 1 for the Y in the equation. it will look like this:
X = 2*1
X = 2


so for the equations X + Y = 3 and X = 2Y

X= 2 and Y= 1
you got it? if not let me know, K?

Answer 5

(1) x + y = 3
(2) x = 2y
_________

substitute x with 2y and plug into (1):

2y + y = 3
3y = 3 /:3 (divide both sides with 3)
y = 1

now plug y = 1 into (2):
x = 2*1
x = 2

Check the system (plug solutions for x and y into both equations). If it works, plugged values should give result that makes left and right sides equal.

for x = 2, and y = 1
(1) x + y = 3 ?
2 + 1 = 3
3 = 3
OK

(2) x = 2y ?
2 = 2*1
2 = 2
OK

System works, and the solutions for x and y are indeed x = 2, y = 1.

Answer 6

Substitute 2Y every time X occurs in X + Y = 3

(2Y) + Y = 3

3Y = 3

Y = 1 if X + Y = 3 then X must equal 2

Answer 7

It's so easy, the equation then becomes, 2Y + Y= 3, so 3Y=3, so Y = 1 and X= 2

Answer 8

X+Y = 3
Because X=2Y so u can substitute x with 2y
so
2Y+Y=3
3Y=3
so Y=1

Because X+Y=3
so X=2

Answer 9

X+Y=3
X=2Y
subsitute 2Y for the X in the first equation
2Y+Y=3
3Y=3
Y=1
replace the Y as 1 into the first equation
X+1=3
X=2

Answer 10

you just need to substitute the x in the first equation with 2y
you should get:
2y+y=3 => 3y=3 => y=1
by knowing that x=2y you get x=2*1=2
simple :P