#color(blue)("("2+3i)")")color(red)("("-3-7i"))#
#color(white)("XXX")=color(blue)(2)color(red)("("-3-7i")")+color(blue)(3i)color(red)("("-3-7i"))#
#color(white)("XXX")=color(brown)(-6-14i)+color(green)(-9i-21i^2#
#color(white)("XXX")=color(brown)(-6-14i)+color(green)(-9i+21#
#color(white)("XXX")=15-23i#