Question

Please solve using elimination.

Answer 1

Answer:

x = -19/3      y =  10      write as an ordered pair (-19/3, -10)

Step-by-step explanation:

Step 1:  'Elimination' is done through adding or subtracting.  You want to add the two equations together to get rid of one of the variables.  

Since the x values have coefficients with opposite signs (-9 and 9), add the two functions together.  The result is...

 -2y = 20            { -9x + 9x = 0, so x is gone, 4y + (-6y) = -2y, 17 + 3 = 20 }

Step 2:  Now solve for the remaining variable, in this case, 'y'

 -2y = 20                    (divide both sides by -2 to isolate the variable)

 

     y = -10            

Step 3:  Plug the value for 'y' into one of the original equations to find 'x'

-9x + 4(-10) = 17          ('y' becomes -10)

  -9x - 40 =  17           {   4(-10) = -40  }  (now add 40 to both sides)

      -9x = 57               (divide both sides by -9 to isolate 'x' )

           x = -57/9           (now reduce, both are multiples of 3, so divide 3 out)

             x = -19/3            (  -57/3 = -19,   9/3 = 3 )