solve the simultaneous equations x=2y+4 and 3x=4-2y?

Answer 1

Plugin the X value from the first equation into the second one:

3(2y+4) = 4-2y -- Now solve for Y
6y +12 = 4-2y
8y = -8
y = -1 -- Plugin the Y value into one of the equations to find X

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

Answer 2

x=2y+4 2y = x - 4
3x = 4-2y 2y = 4 - 3x

then x - 4 = 4 -3x
x + 3 x = 4 + 4
4 x = 8
x = 2
where 2 y = x - 4
2y = 2 - 4
2 y = -2
y = -1
x= 2 , y = -1 s.s ={ ( 2 , -1 ) }

Answer 3

There are lots of ways to do this. Here's one.

Multiply the first equation through by 3:

3x = 6y + 12

Then subtract the second equation from the new first equation:

3x = 6y + 12
-[3x = 4 - 2y]

=> 0 = 8y +8

Now divide both sides by 8 to get

0 = y + 1

Subtracting 1 from both sides gives

y = -1

Now plug this back into either of the original equations to solve for x. The first one is easier:

x = 2*(-1) + 4

so x = 2

The solution is x = 2, y = -1

You can check this in the second equation just to be sure:

3 * 2 = 4 - 2* (-1)
6 = 6, so it's right!

Answer 4

x=2y+4 (equation 1)
3x=4-2y (equation 2)

So substitute equation 1 into equation 2, i.e. wherever you see 'x' in equation 2, replace it with '2y+4'


So we have:
3(2y+4) = 4 - 2y
6y + 12 = 4 - 2y
subtract 12 from both sides:
6y + 12 - 12 = 4 - 2y - 12
6y = -8 - 2y
Add 2y to both sides:
6y + 2y = -8 - 2y + 2y
8y = -8
Divide both sides by 1:
y = -1

So now subsitute y=-1 into equation 1 to find x:
x=2y+4
x=(2*-1) +4
x = -2+4
x=2

So the answer is: x=2, y=-1

Answer 5

3(2y+4) = 4-2y
8y +8 = 0
y = -1
x = -2+4 = 2

Answer 6

Adding gives:-
4x = 8
x = 2

2 = 2y + 4
2y = - 2
y = - 1

Solution is x = 2, y = - 1

Answer 7

x-4=2y 2y=4-3x
x-4=4-3x
x=8-3x
4x=8
x=2 2y=4-(3*2)
2y=4-6
2y=-2
y=-1
therefore x=2 and y=-1

Answer 8

X=2Y+4
3(2Y+4)=4-2Y

X=2Y+4
6Y+12=4-2Y

X=2Y+4
8Y=-8

X=2Y+4
Y=-1

X=2(-1)+4
Y=-1

X=2
Y=-1