Question

solve 5x+2y=4 3x+4y+2z=6 7x+3y+4z=29

Answer 1

I think you start with setting each of the equations equal to 29: 5x+2y=29 solve this one for y (in terms of x) 43x+4y+2z=29 67x+3y+4z=29 combine these two so that you eliminate z y= (29-5x)/2 and (86 - 67)x +(8-3)y = 19x+5y = 29. Now you could use these two equations to solve for x and y...but it's faster if you happen to have a graphing calculator. Graph the two lines and find their point of intersection.....(-4.94486, 26.86214) Now just plug these values in and solve for z....I leave that to you

Answer 2

5x +2y =29 ------------(1)

43x + 4y + 2z = 29 -----(2)

67x + 3y + 4z = 29 -----(3)

2 times equation (2) gives 86x + 8y + 4z = 58 ------(4)

equation (4) - equation (3) gives 19x + 5y = 29 --------(5)

5/2 times equation (1) gives 25/2 x + 5y = 29x5/2 ------(6)

equation (5) - equation (6) gives (19-12.5)x = (29-5x29/2) therefore x = -6.69

substitute x value to equation (1) gives y = 31.225 and substitute x value and y value to equation (2) gives z = 95.885

Answer 3

You would need to use the method of elimination
3x+4y+2z=6
7x+3y+4z=29

So then you could multiple the top by 3 and the bottom equation by -4
So then it would be

9x+12y+6z = 18
-28x-12y-16z=-116

then y would be out. and you would have
-19x-19z = -98 . So then can you do it from there?

Answer 4

then would i just plug in x and z into one of the equations to get y?

Answer 5

Well you would need to manipulate from there, and find each value. You could solve for x and use it, or visa versa,

Answer 6

okay thank you rick

Answer 7

7x + 3y + 4z = 29
3x + 4y + 2z = 6 -->(-2)
---------------
7x + 3y + 4z = 29
-6x - 8y - 4z = -12 (result of multiplying by -2)
---------------add
x - 5y = 17

5x + 2y = 4
x - 5y = 17 -->(-5)
----------------
5x + 2y = 4
-5x + 25y = - 85 (result of multiplying by -5)
----------------
27y = - 81
y = -3

x - 5y = 17
x - 5(-3) = 17
x + 15 = 17
x = 17 - 15
x = 2

7x + 3y + 4z = 29
7(2) + 3(-3) + 4z = 29
14 - 9 + 4z = 29
5 + 4z = 29
4z = 29 - 5
4z = 24
z = 6

check...
3x + 4y + 2z = 6
3(2) + 4(-3) + 2(6) = 6
6 - 12 + 12 = 6
6 = 6 (correct)

x = 2, y = -3 and z = 6