How do solve the following linear system?: # 2x - 3y = 1 , 3x + y = -20 #?

1 Answer
Jul 13, 2016

Answer:

#x = -59/11" and " y = -3 10/11#

Explanation:

The second equation contains a single #y# term, so it is easy to transpose this to give: #y = -3x-20#

We now have an expression for #y# in terms of x and can substitute that into the other equation:

#2x-3color(magenta)y =1 " and "color(magenta)(y = -3x -20#

#2x-3(color(magenta)(-3x -20)) =1#
#2x+9x+60 =1#

#11x= -59#

#color(blue)(x = -59/11)" "#But #y = -3color(blue)x -20#
#y = -3(color(blue)((-59)/11)) -20#

#y = -3 10/11#