How do you solve the system of equations #5x + 5y = - 15# and #2x + 5y = 9#?

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Answer 1 · 2017-06-25T01:38:44

I would solve by subtracting the two equations to eliminate the #y# values.

# 5x + 5y = -15# and subtracting second equation
# -(2x +5y = 9) # this equals

# 3x + 0y = - 24 # divide both sides by 3

#(3x)/3 = -24/3 # which gives

# x = -8 # Now put the #x# value into one of the equations.

# 5(-8) + 5y = -15#

# -40 + 5y = -15 # add 40 to both sides

# -40 + 40 + 5y = -15 + 40 #

# 5y = 25 # divide both sides by 5

# (5y)/5 = 25/5 #

# y = 5 #