>>242-243
0＝|4x+3y-8|^2−|5y+3|^2
＝(4x+3y-8)^2−(5y+3)^2
＝{(4x+3y-8)−(5y+3)}{(4x+3y-8)＋(5y+3)}
＝(4x-2y-11)(4x+8y-5),