How do you solve the following system: #5x + 8y = -2, 3x - 4y = -10#?

1 Answer
EZ as pi
May 10, 2016

# x = -2 and y = 1#

Explanation:

For the elimination method. the coefficients of one of the variable should be the same. It is fantastically easier if they can become additive inverses - same number, different signs. +5 and - 5 add to 0.

#" "5x + 8y = -2 ..................." equ A"#
#" " 3x - 4y = -10....................."equ B"#
#B xx 2: " "6x - 8y = -20 .................... "equ C"#

#A + B:" " 11x " "= -22#
#" " x = -2#

Substitute in A: #5(-2) + 8y= -2# =
#" "-10+8y = -2#
#" " 8y = -2 + 10#
#" " 8y = 8#
#" " y = 1#

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