Solve by substitution

Question

3y-x=-3

y=-2x+6

Answer 1

Teresa, if you substitute in soccer, you substitute a forward for a forward and not for a goalie, right? In math, we can substitute a "value" for a variable for the variable in another equation.

 

Since y = -2x + 6, we can substitute -2x - 6 for y in the first equation...

 

3(-2x + 6) - x = -3

-6x + 18 - x = - 3

-7x = -21

x = 3

 

y = -2(3) + 6

y = 0

 

(3,0) is your answer.

Answer 2

We can plug the second equation into the first

 

3(-2x + 6) - x = -3

 

-6x + 18 - x = -3

 

-7x + 18 = -3

 

-7x = -21

 

x = 3

 

y = -2(3) + 6 = -6 + 6 = 0