Algebra

posted by Ashly

Solve by the elimination method:
7r-9s=-35
9r+7s=85

  1. Judy

    (7r-9s)7=(-35) 7
    (9r+7s)9=85.9
    7(7r-9s)=765
    7(7r-9s)=-35.7
    9(9r+9s)=765
    7(7r-9s)=-245
    9.9r+9.7s=765
    7.7r-7.9s=-245
    81r+63s=765
    49r-63s=-245
    81r+63s=765
    49r-63s=-245
    (81r+63s)+(49r-63s)=765.245
    49r-63s=-245
    1230r=520
    49r-63s=-245
    130r/130=520/130
    49r-63s=-245
    r=2^3-1
    49r-63s=-245
    r=4
    49.4-63s=-245
    196-63s=-441
    63s/63=441/63
    s=7^2-1
    s=7

  2. Jen

    No, no, no, no, no, no, no...I have no idea what all that nonsense above is.
    7r-9s=-35
    9r+7s=85
    Multiply the first equation by 7 and the bottom by 9 so that the s's cancel.
    49r-63s=-245
    81r+63s= 765
    130r=520
    r=4
    Now put r=4 back into any original equation.
    9(4)+7s=85
    36+7s=85
    7s=49
    s=7
    (4,7)

Respond to this Question

First Name

Your Answer

Similar Questions

  1. Algebra

    Solving system of linear equations by using the apropiate method name the method and the x,y coordinates 1)X=4y+8 2x-8y=-3 2)3x-7y=6 elimination method 2x+7y=4 (2,0) 3)5x-2y=12 elimination method 3x-2y=-2 (7,23/2) 4)9x-8y=42 elimination …
  2. algebra

    Solve by elimination method. 2r-5s=-33 5r+2s=48 Solve by substitution method. 5x+6y=5 x-9y=40 I always get these two confused... can someone please help me with these two problems?
  3. math elimination method

    elimination method really confuses me. solve by elimination method 5r -3s = 17 3r + 5s =17 A. solution is ______ (ordered pair, integer or fraction) B. Infinitely many C. No Solution
  4. Algebra

    Solve by elimination method. 7r-3s=14 3r+7s=64 Could never figure out the elimination method. Would love some help with this one. Thanks
  5. MaTh = Algebra = help

    Solve this system of linear equaiton by an algebraic method. So If I had to solve this the elimination method way, how would I do it?
  6. Algebra/Elimination method

    Solve using the elimination method. If the system has no solution or an infinite number of solutions, state this. -27x - 18y = -180 9x + 6y = 60
  7. algebra

    1 Solve the set of linear equations by the matrix method : a+3b+2c=3 , 2a-b-3c= -8, 5a+2b+c=9. Sove for a 2 4 7 3 2 Solve the set of linear equations by Guassian elimination method : a+2b+3c=5, 3a-b+2c=8, 4a-6b-4c=-2. Find a 1 4 5 …
  8. math

    Please solve the system with the elimination method. Explain each step as it is performed. 5y = x 2x - 3y = 7 Would the elimination method have been your first choice to solve this problem?
  9. Algebra 1

    bobpursey, In this problem you helped me with earlier: Solve using any appropriate method. y = 2× - 5, y = ½× + 1 Substitution, substitute for y. 2×-5=½ × + 1 3/2 x=6 x=4 y= 2*4-5=3 How did you choose which method you were going …
  10. College Algebra

    Solve for elimination method,substitution method and cramer's rule for 8x - 4y + 2z =16

More Similar Questions