Solve this system of equations using elimination: 2x + 3y = 20 and -10x + 5y = 20. Write your answer as a point, (x,y). Remember: No spaces.

Question

Solve this system of equations using elimination: 2x + 3y = 20 and -10x + 5y = 20. Write your answer as a point, (x,y). Remember: No spaces.

Answer 1

2x + 3y = 20              eq1

-10x + 5y = 20           eq2

 

Multiply eq1 by -5 so that both equations have the same coefficient of x.

 

-10x - 15y = -100        new eq1

-10x + 5y = 20                eq2

 

 

Subtract eq2 from new eq1 to eliminate the x terms.

 

-20y = -120

 

 

Divide both sides of the equation by -20.

 

y = 6

 

 

Substitute this value of y into eq1 to solve for x.

 

2x + 3(6) = 20

 

2x + 18 = 20

 

2x = 2

 

  x = 1

 

Your solution is  (1, 6).