math

posted by .

5x+4y-5z=44
3x-4y+3z=-10
6x-3y+6z=-15
help solve it

  • math -

    Your goal is to go from 3 equations in 3 variables down to 2 equations in 2 variables.

    It is up to you to decide which variable you want to eliminate. I think I might try eliminating the y.

    Add the first two equations together. since the y's are equal and opposite they will eliminate easily.

    5x+4y-5z = 44
    3x -4y +3z = -10

    8x -2z = 34

    since there is a common factor of 2, you can rewrite this equation as

    4x-z =17 SAVE this EQ.

    Since I haven't used the 3rd equation, I have to use it now. Since we have -3y in that equation, I will choose the first eq. to use again. That equation has a 4y. I am going to multiply by 3 and 4 to get 12y and -12y so they will cancel.

    15x+12y -15z =132
    24x -12y + 24z -60

    39x -9z = 72

    Recall the equation we saved:

    4x - z = 17

    I would multiply this equation by -9 and add it to the other one. That will eliminate z and you will solve for x.

    Once you have x... find z in one of these two equations.

    Once you have x, and z. Go back to one of the original equations and find y.

    Once you have x, y, and z. Check all three values in all three equations. It is important to check because it is very, very easy to make a mistake. These are tricky and there are many places where you can make a mistake.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. math

    actually, in a addition to the question i posted a few minutes ago, can someone please help me with a few actual specific questions?
  2. Math

    Solve by eliminnation methods 2x-4y=5 2x-4y=6 solve the system by elimination method 5x+2y= -13 7x-3y=17 Solve x+6<-7 or x+6>4 Determine whether the given numbers are solutions of the inequality 8,-10,-18,-3 y-8>2y-3 Solve …
  3. MATH PLEASE HELP!

    Solve each system 3x+2y= -2 9x- y= -6 I know how to solve for x but i get really lost trying to figure out how to solve for the second variable
  4. MATH PLEASEEEEE

    I have a question, if f(x)=x/2 and g(x)=3x+1 find: a) (f+g)(x) i know you go x/2+3x+1. but how do i solve that?
  5. math

    solve for the indicated variable: a. temperature formula solve for F: K=5/9(F-32)+273 b. annual interest rate solve for R: A=P+Prt can you please show how to do these?
  6. Math

    Solve for S: r^2s-5s=7. Solve for b: L= 4a^2b. I'm confused about how to solve these problems. Could someone show me the steps?
  7. Math

    We have an important chemsitry test due and I want to make sure that I do not mess up on my algebra. I am dealing with the integrated rate law, but my question is purely algebraically in nature. I hope, somebody can help me. 1) ln(A) …
  8. English

    1. He can not solve the math problem. 2. He cannot solve the math problem. 3. He can't solve the math problem. 4. He could not solve the math problem. 5. He couldnot solve the math problem. 6. He couldn't solve the math problem. (Are …
  9. English

    I'm worried about my math. 1. Why don't you buy a math self- teaching book and solve math problems a lot. 2. Why don't you buy a math self-study book and solve math problems a lot. 3. Why don't you go to a math academy and study math …
  10. Alebra

    Solve 5m - 8 > 12 Solve 12 - 3a > 18 Solve 5m - 4 < 2m + 11 Solve 2r - 18 ≤ 5r + 3 Solve 26p - 20 > 14p + 64 Can someone give me an example to one of these?

More Similar Questions