Question

Need help will give medal!!



We are doing systems of equations in three variables...

-3a - 4b + 2c = 28
a +3b - 4c = -31
2a + 3c = 11

Answer 1

Will you help? @texaschic101

Answer 2

-3a - 4b + 2c = 28 ---(multiply by 3)
a + 3b - 4c = -31----(multiply by 4)
--------------
-9a - 12b + 6c = 84 (result of multiplying by 3)
4a + 12b - 16c = - 124 (result of multiplying by 4)
--------------add
-5a - 10c = - 40

2a + 3c = 11 ----(multiply by 5)
-5a - 10c = -40 ---(multiply by 2)
-------------
10a + 15c = 55 (result of multiplying by 5)
-10a - 20c = -80 (result of multiplying by 2)
--------------add
-5c = - 25
c = 5

2a + 3c = 11
2a + 3(5) = 11
2a + 15 = 11
2a = 11 - 15
2a = -4
a = -2

a + 3b - 4c = -31
-2 + 3b - 4(5) = -31
-2 + 3b - 20 = -31
-22 + 3b = -31
3b = -31 + 22
3b = - 9
b = -3

check...
-3a - 4b + 2c = 28
-3(-2) - 4(-3) + 2(5) = 28
6 + 12 + 10 = 28
28 = 28 (correct)

so...a = -2, b = -3, and c = 5

Answer 3

THANK YOU SO MUCH!!!!!! I have one more question if you don't mind helping me

Answer 4

I don't mind...but I can't make any promises that I will know it

Answer 5

its ok you are 100 times smarter than me and i appreciate your help

Answer 6

4x + 2y + 6z = 61
-12x + 3y - 5z + 8
-4x + 7y + 7z + 34

Answer 7

4x + 2y + 6z = 61---(multiply by 3)
-12x + 3y - 5z = 8
-----------------
12x + 6y + 18z = 183 (result of multiplying by 3)
-12x + 3y - 5z = 8
----------------add
9y + 13z = 175

4x + 2y + 6z = 61
-4x + 7y + 7z = 34
----------------add
9y + 13z = 95

9y + 13z = 175 -- multiply by -1
9y + 13z = 95
----------------
-9y - 13z = -175
9y + 13z = 95
------------------add
0 = - 80 (INCORRECT)

This has no solution

Answer 8

sorry it took so long but I was having problems with it....I do not think it has a solution.
I am sorry but I have to go now....I will be back on later.

Answer 9

Thank you again!!!!

Answer 10

x + 2y + 12
3y - 4z = 25
x + 6y + z = 20

will you help me with this one??

Answer 11

Will you please help me?? @Directrix

Answer 12

Something is missing from the first equation you posted.

x + 2y + 12 equals what?

Answer 13

@~Joelie~ ^^^^

Answer 14

oh my bad its suppose to be x + 2y = 12

not + 12

Answer 15

@Directrix

Answer 16

Click on the attachments.