How do you solve the system of equations #-3x-4y=0# and #y = -5x - 17#?

Question

2803 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-12-31T20:24:20

#x = -4#
#y = +3#

#-3x-4y=0#
#y=-5x-17#

Substitute the second term of the second equation to the first one:
#-3x-4(-5x-17)=0#
#y=-5x-17#

Solve the first one:
#-3x+20x+68=0#
#y=-5x-17#

#17x+68=0#
#y=-5x-17#

#17x=-68#
#y=-5x-17#

#x=-4#
#y=-5x-17#

Substitute #-4# to the #x# in the second equation:
#x=-4#
#y=-5(-4)-17#

#x=-4#
#y=20-17#

Result:
#x=-4#
#y=3#