3x+9y=-42-3x+2y=-2
6x+9y=-42+2y=-2 <----add 3x to both sides where x value is present
6x+7y=-42=-2 <---- subtract 2x on both sides where y value is present
6x+7y=-40 <---- add 2 to both sides where applicable.
y= -5.71
x = -6.66
(This is only if you use the blocking method to find the values of x and y.)