How do you show work for x+y=20 x-y=4?

Question

Using elimination. The answer is 12 and 8. Show work?

Answer 1

THERE ARE TWO STEPS !

FIRST STEP:-
In x+y=20,
their should be following cases:

1) x=0 and y=20

2) x=1 and y=19

3) x=2 and y=18

4) x=3 and y=17

5) x=4 and y=16

6) x=5 and y=15

7) x=6 and y=14

8) x=7 and y=13

9) x=8 and y=12

10) x=9 and y=11

11) x=10 and y=10

12) x=11 and y=9

13) x=12 and y=8

14) x=13 and y=7

15) x=14 and y=6

16) x=15 and y=5

17) x=16 and y=4

18) x=17 and y=3

19) x=18 and y=2

20) x=19 and y=1

21) x=20 and y=0



By using above value,

calculate the x-y = 4 .

Then the value which x-y = 4 is the answere.

Thus, x=12 and y=8.



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SECOND STEP:-


It is the very easy step.

Calculate the substraction of the equation x+y = 20 and x-y=4


x + y = 20
-
x - y = 4
--------------------------------
y + y = 16

Therefore,

y + y = 16

=> 2y = 16
=> y = 16/2
=> y=8

The value of y is calculated. So, lets find the value of x
1)
x + y = 20
=> x + 8 = 20
=> x = 20 - 8
=> x = 12

2)
x - y = 4
=> x - 8 = 4
=> x = 4 + 8
=> x = 12

Therefore x=12

Thus x =12 and y = 8.

Answer 2

Listen buddy - I don't know what grade you're in now, but if you ask something like this, you better improve your skills asap - I'll start by helping you out:
I am not 100 percent sure which technique you mean by "elimination" because both techniques kinda do that, but anyway - all you do is write the equations one below the other and then, you can add them, subtract them to create a new equation that will still be true and leave you with only ONE variable to solve - here:
x + y = 20
-
x - y = 4
--------------------
2y = 16

and of course: y=8, x=y+4=12
What I chose to do is subtract eq B from eq A. By doing that, the x-s say bye bye and then you have +y - -y = 2y.
Get the trick?

Answer 3

Several ways but
x + y = 20
x - y = 4
__________
adding
2x = 24
div both sides by 2
2x/2 = 24/2
x = 12
the by substitution
12 + y = 20
subtracting 12 from both sides
12 - 12 + y = 20 - 12
y = 8
you can check solution by substituting in 2nd equation
12 - 8 = 4
4 = 4

Answer 4

Take first equation above and solve for x. To do so add or subtract the same amount on both sides of the equal sign so as to get the x alone:
x+y=20
x+y-y=20-y
x+0=20-y
x=20-y

Now take second equation and substitute the value you now have for x:
x-y=4
(20-y)-y=4
20-2y=4
20-2y-20=4-20
-2y=-16
y=8

Now take the second equation again and substitute for y to solve for x:

x-y=4
x-8=4
x-8+8=4+8
x=12

Answer 5

x+y = 20 (1)
x-y = 4 (2)

Add equations (1) & (2)
2x=24
Therefore x = 24/2 = 12

Subsituting value of x in equation (1)
12+y=20
y=20-12
y=8

What is surprising to me is that, if you can operate a PC, Internet and Yahoo Answers then solving this should have been child's play.

Answer 6

x + y = 20 -------------- (1)
x - y = 4 -------------- (2)
Adding eq. (1) + (2) to eliminate y
2x = 24
x = 12
Substituting x = 12 in eq. (1)
12 + y = 20
y = 20-12
y = 8

Answer : x = 12 & y = 8

Answer 7

1st value of y:
x + y = 20
y = 20 - x

2nd value of y:
x - y = 4
y = x - 4

Value of x:
20 - x = x - 4
2x = 24
x = 12

Value of y:
y = 20 - x
y = 20 - 12
y = 8

Answer: x = 12, y = 8

Proof 1:
x + y = 20
12 + 8 = 20

Proof 2:
x - y = 4
12 - 8 = 4

Answer 8

short answer: y=32 via flow multiplying long answer: positioned the y over x: (Y)20 --------- (X)5 Then positioned the (X)8 throughout the time of from the (X)5, because of the fact we are going to coach how the share continually maintains to be the comparable: (Y)20 -------- -------- (X)5 (X)8 (20/5=?/8) Now flow multiply the (Y)20 and the (X)8 (Y)20 -------- one hundred sixty -------- (X)5 (X)8 (20x8=one hundred sixty) Now divide the (X)5 via one hundred sixty (Y)20 (Y)32 -------- one hundred sixty -------- (X)5 (X)8 (5 divided via one hundred sixty=32) So your answer is Y=32 i'm sorry the fractions are actually not straight forward to verify, yet once you write it down, it rather is much less complicated to verify it.

Answer 9

x + y = 20
x - y = 4--------ADD

2x = 24
x = 12

12 + y = 20
y = 8

x = 12 , y = 8

Answer 10

why don't you just work it out?