SOLUTION: 1.Use the Substitution method to solve the system of equations. x + y = 10 y = x + 8 2.Use the Substitution method to solve the system of equations. 3x + y = 5 4x -

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Question 203093: 1.Use the Substitution method to solve the system of equations.
x + y = 10
y = x + 8
2.Use the Substitution method to solve the system of equations.
3x + y = 5
4x - 7y = -10
3.Use the Substitution method to solve the system of equations.
y - 2x = -5
3y - x = 5

can you please help me solve each step by step so i can under stand

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
# 1


Start with the given system of equations:





Start with the second equation.


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


Move onto the first equation.


Plug in .


Combine like terms on the left side.


Subtract from both sides.


Combine like terms on the right side.


Divide both sides by to isolate .


Reduce.


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


Since we know that , we can use this to find .


Go back to the second equation.


Plug in .


Add


So the solutions are and .


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of (red) and (green)





# 2



Start with the given system of equations:





Start with the first equation.


Subtract from both sides.


Rearrange the terms and simplify.


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


Move onto the second equation.


Now plug in .


Distribute.


Combine like terms on the left side.


Add to both sides.


Combine like terms on the right side.


Divide both sides by to isolate .


Reduce.


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


Since we know that , we can use this to find .


Go back to the first equation.


Plug in .


Multiply.


Subtract from both sides.


Combine like terms on the right side.


So the solutions are and .


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of (red) and (green)





# 3



Start with the given system of equations:





Start with the first equation.


Add to both sides.


Rearrange the terms and simplify.


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


Move onto the second equation.


Now plug in .


Distribute.


Combine like terms on the left side.


Add to both sides.


Combine like terms on the right side.


Divide both sides by to isolate .


Reduce.


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


Since we know that , we can use this to find .


Go back to the first equation.


Plug in .


Multiply.


Add to both sides.


Combine like terms on the right side.


So the solutions are and .


This means that the system is consistent and independent.


Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.


Graph of (red) and (green)

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