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Algebra one help! HElp is much needed and appreciated! :)?

0 votes
please solve the systems. :)
1) -6x + 8y = -6
3x - 3y = 3

2) -7x + 39 = -4y
-3x - 2y = -39

solve by the substitution method.
3) x + y = -5
x + y = 9
asked Nov 9, 2013 in ALGEBRA 1 by andrew Scholar

1 Answer

0 votes

1) -6x + 8y = -6 ------- (1)
     3x - 3y = 3  --------- (2)

(1) + (2)*2 ⇒-6x+8y =-6

                   6x-6y = 6

                  __________

                      2y = 0

Apply division property, divide by 2 to each side.

                 2y/2 = 0/2

                    y = 0

Substitute the y value in (1)

-6x+8*0 = -6

-6x = -6

Apply division property, divide by negitive 6 to each side.

-6x/-6 = -6/-6

x = 1

Solution x = 1, y = 0

2) -7x + 39 = -4y
-3x - 2y = -39

-7x+4y = -39 ------------ (1)

-3x-2y = -39 ------------- (2)

(1)+(2)*2 ⇒ -7x+4y = -39

                 -6x-4y = -78

               _______________

               -13x = -117

                x = -117/-13

                x = 9

Substitute the x value in (1)

-7*9+4y = -39

-63+4y = -39

4y = -39+63

4y = 24

y = 24/4

y = 6

Solution x = 9, y = 6

3) x + y = -5
x + y = 9

From the above equations -5 = 9

This is not possible.

The system has no solution

answered Nov 9, 2013 by william Mentor

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