How do you solve the system of equations #-x-y=15# and #-8x+8y=24#?
1 Answer
Explanation:
The system of equations given to you looks like this
#{( -color(white)(1)x - color(white)(1)y = 15), (-8x + 8y = 24) :}#
Notice that one equation features
To do that, multiply the first equation by
#{( -color(white)(1)x - color(white)(1)y = 15" " | xx 8), (-8x + 8y = 24) :}#
this will get you
#{ ( -8x - 8y = 120), (-8x + 8y = color(white)(1)24) :}#
Now you're ready to add the two equations
#{ ( -8x - 8y = 120), (-8x + 8y = color(white)(1)24) :}#
#color(white)(aaaaaaaaaaaaaaa)/color(white)(a)#
#-8x + (-8x) - color(red)(cancel(color(black)(8y))) + color(red)(cancel(color(black)(8y))) = 120 + 24#
#-16x = 144 implies x = 144/(-16) = -9#
Take this value of
#- (-9) - y = 15#
#-y = 15 - 9 implies y = -6#
Therefore, the two solutions to your system of equations are
#{(x=-9), (y=-6) :}#