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),

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

$-18 + 22y= 77$

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

How do you solve the following system?: 9x +2y = 7 , -42x - 2y = -19x +2y = 7 , -42x - 2y = -1