若根号x+y-1+(y+3)²=0,求(5x-y)·(2x+3y)的值.急急急!快快快!_数学解答

若根号x+y-1+(y+3)²=0,求(5x-y)·(2x+3y)的值.
急急急!快快快!

人气：473 ℃　时间：2020-03-28 07:35:12

解答

根号x+y-1+(y+3)²=0
则 x+y-1=0,x+y=1
y+3=0,y=-3,x=4
(5x-y)·(2x+3y)
=(20+3)(8-9)
=-23