How do you solve 3x + y = 2 and 4x + y = 20?

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Answer 1 · 2015-10-13T07:49:59

# color(green)(x = 18#
# color(green)(y = -52#

#3x + y = 2# --------(1)
#4x + y = 20 #------(2)

To eliminate #y# we can subtract (1) from (2)

#(4x+y) - (3x+y) = 20 -2#

# (4x - 3x) + (y - y) = 18#

# color(green)(x = 18#

Substituting #x = 18# in (1) we get

#3(18) + y = 2#

#54 + y = 2#

Transposing 54 to the right hand side, we get

#y = 2 - 54#

# color(green)(y = -52#