Solve the second equation for x ( x = -13 - 3y) and then substitute the value into first equation
Solve the first equation for y( y = 2x - 9 ) and then substitute that value into second equation
solve either equation for 3y ( 3y = -13 - x or 3y = 6x - 27) and then substitute that value into other equation
Solution:
Given system of equations are:
6x - 3y = 27 ------- eqn 1
x + 3y = -13 -------- eqn 2
We have to solve the above system of equations by substitution method
Solve the second equation for x ( x = -13 - 3y) and then substitute the value into first equation
Solve the eqn 2 for variable "x"
From eqn 2,
x + 3y = -13
x = -3y - 13 ------- eqn 3
Substitute eqn 3 in eqn 1
6(-3y - 13) - 3y = 27
-18y - 78 - 3y = 27
Combine the like terms
-18y - 3y - 78 = 27
-21y = 27 + 78
-21y = 105
y = -5
Substitute y =-5 in eqn 2
x + 3(-5) = -13
x - 15 = -13
x = -13 + 15
x = 2
Thus the solution is (x, y) = (2, -5)