How do you solve the following system?: #9x +2y = 7 , -42x - 2y = -1#

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Answer 1 · 2018-07-02T04:23:23

#color(blue)(x = -2/11, y = 95/22#

#9x + 2y = 7, " Eqn (1)"#

#-42x - 2y = -1. " Eqn (2)"#

#"Adding Eqns (1) & (2)"#,

#9x cancel(+ 2y) - 42x cancel(- 2y) = 7 - 1#

#-33y = 6 " or " x = -6/33 = -2/11#

Substituting value of x in Eqn (1),

#(9 * (-2/11)) + 2y = 7#

#-18 + 22y= 77#

#y = (77 + 18) / 22 = 95/22#