How do solve the following linear system?: #9x + 1 = -4y, 7x - 2y - 13 = 0 #?

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Answer 1 · 2018-03-05T16:26:43

#color(blue)(x = -62/5), color(green)(y = 27/5)#

#9x + 1 = -4y# Eqn (1)

#y = (9x + 1) / -4#

#7x - 2y = 13# Eqn (2)

Substituting value of yin Eqn (2),

#7x - (2 * (9x + 1)/-4) = 13#

#-28x + 18x + 2 = -52#

#-10x = - 54# or #x = 27/5#

Substituting value of x in Eqn (1),

#y = (9 *(27/5) + 1) / -4 = (243 + 5) / -20 = -62/5#