If #(color(blue)x,color(red)y)=(color(blue)4,color(red)2)# is a solution for both
[1]#color(white)("XXX")color(green)acolor(blue)x-color(magenta)bcolor(red)y=4color(white)("XX")#and#color(white)("XX")#[2]#color(white)("XXX")color(magenta)bcolor(blue)x-color(green)acolor(red)y=10#
then
[3]#color(white)("XXX")color(blue)4color(green)a-color(red)2color(magenta)b=4color(white)("XX")#and#color(white)("XX")#[4]#color(white)("XXX")color(blue)4color(magenta)b-color(red)2color(green)a=10#
Re-sequencing the terms on the left side of [4] and multiplying by #2#
[5]#color(white)("XXX")-4color(green)a+8color(magenta)b=20#
Adding [3] and [5]
[3]#color(white)("XXXX")4color(green)a-2color(magenta)b=4#
[5]#color(white)("XXX")underline(-4color(green)a+8color(magenta)b=20)#
[6]#color(white)("XXXXXXxX")6color(magenta)b=24#
[7]#color(white)("XXX")rarrcolor(white)("XX"X)color(magenta)b=4#
Substituting #4# for #color(magenta)b# in [3]
[8]#color(white)("XXX")color(blue)4color(green)a-color(red)2 * 4 = 4#
Dividing by #4#
[9]#color(white)("XXX")color(green)a-2=1#
[1]#color(white)("XXX")rarrcolor(white)("X")color(green)a=3#
