How do you solve by substitution #y = 2x + 4# and #y = 3x #?

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Answer 1 · 2015-06-10T19:54:57

#x=4#
#y=12#

#y=3x# is already solved for #y#. Substitute it into the other equation.

#y=2x+4# =

Substitute #3x# for #y# and solve for #x#.

#3x=2x+4# =

#x=4#

Substitute #4# for #x# in the equation #y=3x#.

#y=3(4)# =

#y=12#

Check by substituting the values for #x# and #y# into both equations.

First equation.

#y=2x+4# =

#12=2(4)+4# =

#12=12# Check.

Second equation.

#y=3x# =

#12=3(4)# =

#12=12# Check.