Algebra

posted by .

I am solving sytems of equations algrbraically. I have tried several times and I am not comming up with he answers for the following three equations that the book gives.

1) 4x-2y=-5
-x+2y=2

Answer in book: -1,1/2

2) -5x+2y=10
5x-3y=-10

Answer in book: -2,0

3) 2x-y=2
-2y+4y=-5

Answer in book: 1/2,-1

  • Algebra -

    4x-2y=-5
    -x+2y=2

    Adding the two equations together gives

    4x-2y+-x+2y=-5+2

    the ys on the LHS cancel to give

    4x-x=-3
    3x=-3
    x=-1

    substitute x=-1 into one of the starting equations.

    4(-1)-2y=-5
    -4-2y=-5

    -2y=-1
    y=1/2

    Have a go at the others.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. TO DRWLS/MATH HELP PLEASE

    How do i solve inequalitites with three variables. I still can't figure it outplease help. x+y=1 y-z=-3 2x+3y+z=1 THE ANSWERS ARE X=3,Y=-2,Z=1 i KNOW THE ANSWERS I JUST DON'T KNOW HOW THE BOOK GOT THE ANSWERS . i 'VE TRIED MANY DIFFERENT …
  2. Algebra

    I am trying to solve the sytems of equations using the elimination method. 2x+4y=10 -3x+3y=-6 I tied multiplying the first equation by 2 and the second by 4. Then I tried multiplying the first equation by -3 and the secondy by 3. The …
  3. Algebra

    I am solving for sytems of equations using the elimination method. Book says answers are 0,-1. I have tried solving for both x & y using both the 5 and 25 . I am not getting the 0,1 as my answer. 5x-5y=5 25x-25y=22
  4. Algebra

    Solving for the sytems of equiation using the elimination method. Book gives answers 3,2. I have tried using all the numbers to solve for x and y. I do get the 3,2. Don't know if this is another error in the book. 8x-4y=16 4x+5y=22
  5. Algebra

    Mutiplying a Binomial by a Trinomial (FOIL) First, Outer, Inner, Last Method (3X+2)(X-1)(X+3) I have tried equation several times. The book says the answer is: 3X 3rd + 8X 2nd - 5X -6 I get: 12X 2nd - 6X + 3X 3rd -4 Not sure if i am …
  6. Algebra

    Solving quadriatic equaitons using factoring. X^2-6=30-3x^2 The answer in the book is -3,3. I have tried to work the problem several times. I am not getting this answer.
  7. algebra attn Reiny

    Thanks for your help with the solving of the three equations! Yes, it was a typo. I just finished solving it a long way, solving for the 1st 2 equations then the 2nd and 3rd and plugging in variables...etc. etc. Your way gave the same …
  8. Algebra

    I have this math probelm z-(3z)/(2-z)=(6)/(z-2) in my book it says to solve the equation. I have worked this problem many times and I keep comming up with different answers. When I use an online calculator to check my work it is giving …
  9. Algebra 2

    Exponential Notation Simplify. (-2)^0-(-2)^3-(-2)^-1+(-2)^4-(-2)^-2 I tried solving this problem a few times and kept getting random answers. The answer in the book says that it is 25 1/4 I do not understand how you get that answer. …
  10. Physics

    You are given vectors A = 5.0i - 6.5j and B = -2.5i + 7.0j. A third vector C lies in the xy-plane. Vector C is perpendicular to vector A and the scalar product of C with B is 15.0. Find the x and y components to vector C. Here's the …

More Similar Questions