Question

Solve the following system of equations without graphing: 72 + 3y = 53 - 4x + 10y = 29 ) Write your solution as an ordered pair ( (Remember: you want to eliminate one of the variables)

Answer 1

1 72x + 3y= 53

2 -4x + 10y= 29

We are going to multiply our second equation by 18, in order to change the coefficient of x .

2 18*-4x + 18*10y= 29*18

2 -72x + 180y = 522

Then we add the last equation to the first equation

1 72x + 3y= 53

+

2 -72x + 180y = 522

----------------------------------

183 y = 575

y= 575/183

Solving for y we get y= 3.14

Then we replace y in the equation 2 to get x. but first we need to isolate x

2 -4x + 10y= 29

2 -4x = 29 - 10y

2 x = (29 - 10y)/-4

2 x = 0.605

The final answer must be ( 0.605 , 3.14 )