algebra 1 helP?

1) solve by substituting the y in the first equation for the y in the second equation....
2 ( 2x + 4 ) - 3x = 11
then solve for x
4x + 8 - 3x = 11 ----> x = 3
then put the value of x back to either equation & solve for y
y = 2 ( 3 ) + 4 -----> y = 10
>>>>>> x = 3, y =10 <<<<<<<<
2) line both equations corresponding to x, y, & constants .....
4x + 2y = -8
-2x + 3y = 12
then try to eliminate one unknown (x or y)
if you chose x...you should multiply the second equation by 2
4x + 2y = -8
2(-2x + 3y = 12) ----> -4x + 6y = 24 then add each columns to get 8y = 16 and you get y = 2
then plug it back into either equation
4x + 2(2) = -8 solve for x ----> x = -3
>>>>>>> x = -3, y=2 <<<<<<<<

another way is:
if you chose to eliminate y then find a value that each equation will have the same value and make one of the y negative
-3(4x+2y=-8)------> -12x - 6y = 24
2(-2x+3y=12)-----> -4x + 6y = 24
add each equation and solve for x
-16x = 48 ----> x = -3
plug the value of x back into either equation
4 (-3) + 2y = -8 and solve for y
y = 2

1)
y = 2x + 4 (solve by substitution)
2y - 3x = 11

y = 2x + 4
2y = 2(2x + 4)

2y - 3x = 11
2(2x + 4) - 3x = 11
4x + 8 - 3x = 11
4x - 3x = 11 - 8
x = 3

y = 2x + 4
y = 2(3) + 4
y = 6 + 4
y = 10

∴ x = 3 , y = 10

= = = = = = = =

2)
4x + 2y = -8 (solve by elimination)
-2x + 3y = 12

-2x + 3y = 12
-2(-2x + 3y) = -2(12)
4x - 6y = -24

...4x + 2y = -8
--4x - 6y = -24
--------------------
8y = 16

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

4x + 2y = -8
4x + 2(2) = -8
4x + 4 = -8
4x = -8 - 4
4x = -12
x = -12/4
x = -3

∴ x = -3 , y = 2

For number 1 I'd suggest the Substitution Method:
We know what y is equal to, because they tell us: It's 2x + 4. Use this in the next equation:
2y-3x=11
2(2x + 4) - 3x = 11. From here you get:
4x + 8 - 3x = 11. From there you're on your own!

For number 2 I'd suggest the Elimination method:
Focus on the second equation, -2x + 3y = 12. Double it and you get:
-4x + 6y = 24. Now add that to the first equation:
4x + 2y = -8
-4x + 6y = 24
0x + 8y = 16. Notice how the terms with 'x' cancel each other out? No more 'x' to worry about, which is exactly why we did what we did. Again, you take it from there.

1) Use first in second eqn
2(2x+4) - 3x = 11 so that 4x +8-3x = 11 or x =3 and then from the first, y = 10.

2) write them as 2x+y= - 4 and -2x + 3y = 12 then add them so 4y = 8 or y = 2 from the first 2x = -6 so x = -3.