How do you solve # y = -3x + 5# and #5x - 4y = -3# using substitution?

1 Answer
Mar 13, 2016

Answer:

#x=1#
#y=2#

Explanation:

#1#. Start by labelling the equations.

Equation #1#: #color(orange)(y=-3x+5)#

Equation #2#: #color(blue)(5x-4y=-3)#

#2#. Substitute equation #1# into equation #2#.

#color(blue)(5x-4y=-3)#

#color(blue)(5x-4color(orange)((-3x+5))=-3)#

#3#. Solve for #x#.

#5x+12x-20=-3#

#17x=17#

#color(green)(|bar(ul(color(white)(a/a)x=1color(white)(a/a)|)))#

#4#. Substitute #color(red)(x=1)# into equation #1# to find the value of #y#.

#color(orange)(y=-3x+5)#

#color(orange)(y=-3color(red)((1))+5)#

#5#. Solve.

#y=-3+5#

#color(green)(|bar(ul(color(white)(a/a)y=2color(white)(a/a)|)))#

#:.#, #x# is #1# and #y# is #2#.