How do you solve the following system?: 6x +5y =-1 , -5x -9y = 5

1 Answer
Mar 24, 2018

x = 16/29
y = -25/29

Explanation:

For solving using substitution method you have to separate out the value of any one variable (x or y) in any of the equation and put it in the other equation.
Assuming 6x + 5y = -1 to be equation 1 and -5x - 9y = 5 be equation 2
Seperating out the value of x
x = (-1 - 5y)/6 and now putting it in the second equation
-5((-1-5y)/6) - 9y = 5
5((1+5y)/6) - 9y = 5
((5 + 25y)/6) - 9y = 5
Now on taking LCM on LHS
((5 + 25y - 54y)/6) = 5
(5 + 25y - 54y) = 30
5 - 29y = 30
29y = -25
y = -25/29
Now put the value of y in any of the two equations
(6x + 5(-25/29)) = -1
(6x -125/29) = -1
6x = 125/29 - 1
6x = (125-29)/29
6x = 96/29
x = 16/29