solve for x ?

Question

they give u 2 equations and u have to solve for x.

3x+y=12 ,
2x-y=18

Answer 1

3x + y = 12- - - - - - - -Equation 1
2x - y = 18- - - - - - - - Equation 2
- - - - - - - - -
5x = 30

5x / 5 = 30 / 5

x = 30 / 5

x = 6

Insert the x value into equation 1
- - - - - - - - - - - - - -

3x + y = 12

3(6) + y = 12

18 + y = 12

18 + y - 18 = 12 - 18

y = - 6

Insert the y value into equation 1
- - - - - - - - - - -

Check for equation 1

3x + y = 12

3(6) + (- 6) = 12

18 - 6 = 12

12 = 12

- - - - - - - -

Check for equation 2

2x - y = 18

2(6) - ( - 6) = 18

12 + 6 = 18

18 = 18

- - - - - - - - - -

Both equation balance

The solution set is { 6, - 6 }

- - - - - - - - s-

Answer 2

first solve each equation for y and set them equal to each other so 12 - 3x = 2x - 18
add 3x to each side, 12 = 5x - 18
add 18 to each side, 30 = 5x
divide by 5,
so x = 6

Answer 3

we have:

3x + y = 12 (1)
2x - y = 18 (2)

we do the respecting operations in (1) and (2):

adding 3x and 2x:

3x + 2x = 5x

Substracting the y's:

y - y = 0

adding 12 and 18

12 + 18 = 30

Then:

5x = 30

isolating x:

x = 30/5
x = 6

Answer 4

x=6

Answer 5

3x+y=12
2x-y=18
Just add the two equations getting:
5x = 30
x = 6

Isn't it nice that the y terms dropped out?

Answer 6

Use the addition method....
5x=30, since y negates itself.
x= 6 I think, don't forget in other problems to go back and solve for y, when it exists. (By replacing all x's in the equation with the 6 answer, you can do regular equations and solve for y.)

Answer 7

y=12-3x

so, 2x-(12-3x)=18
then it's 2x-12+3x=18
so, 5x=30

x=6


please try to recheck

hey, why are we the ones anwering your homework? hmmm.. you have to learn yourself. i challenge you. solve for y in the same equation. :-)

Answer 8

Adding gives:-
5x = 30
x = 6
18 + y = 12
y = - 6
Solution is x = 6 , y = - 6

Answer 9

add the two equations together to get y to cancel out. Once you add them, you get

5x = 30

From there, it's pretty easy to see that x = 6.

Answer 10

i think it is 4 cuz most the answers r the same so tht is my answer to that question u have asked us all