SOLUTION: how do u solve a system by substitution x+y=14 and -7x+7y=-14

Question 231232: how do u solve a system by substitution x+y=14 and -7x+7y=-14

Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
x + y = 14
-7x + 7y = -14

Solve for y in the first equation to get:

y = 14 - x

Substitute for y in the second equation to get:

-7x + 7 * (14-x) = -14

Solve for x.

Remove Parentheses to get:

-7x + 7*14 - 7x = -14

Combine like terms to get:

-14x + 7*14 = -14

subtract 7*14 from vboth sides to get:

-14x = -14 - 7*14

Simplify and combine like terms to get

-14x = -112

Divide both sides by -14 to get:

x = 8
Now that you have x = 8, go back to your first equation and solve for y

Your first equation is:

x + y = 14

Replace x with 8 to get:

8 + y = 14

Solve for y to get y = 6

You have:

x = 8
y = 6

Substitute in second equation to get:

-7*8 + 7*6 = -14

This becomes -56 + 42 = -14 which becomes -14 = -14 which is true.

Values of x = 8 and y = 6 are good.

RELATED QUESTIONS
how can I solve this solve each system of equations by substitution method -3x+7y=14... (answered by lenny460)

How do I solve this system? -7x+3y+3z=8 x=y-5z+14 y=8z-22 Substitution is the... (answered by Alan3354)

solve by substitution method 6x+7y=14 x=... (answered by mananth)

How do I solve and check the following solving by substitution. 7x + 5y = -24 x = 28 (answered by Alan3354)

Solve the given system by the substitution method 4x+y=14... (answered by Alan3354)

How do i solve a system of equations by graphing such as 7x-7y=35... (answered by richwmiller)

solve the system 7x+3y=-2... (answered by checkley71)

How do I solve by substitution of linear equation? x=y+2... (answered by drj)

-7x+y=11 2x+4y=14 how do i solve this using... (answered by Theo)