整数x、y满足等式x2 + y2 + 7 = 4x + 4y,则x + y的值是多少?

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/16 15:59:30
整数x、y满足等式x2 + y2 + 7 = 4x + 4y,则x + y的值是多少?
xQJ@ $$! fo*H.dUV4BЍPZ3ڙd/8cu,{=M&r9ι\>4/ՈagzL=VW./EVɛx, >> IͭC2Zc!70ԑ9,P'8VMfwUÛٽ/FŻbamSbwE̯;h޳V˧dh8Pl*)Hъ=C{*o2C M1z:nWRgI{fW[S;#_Kc`X_lP 

整数x、y满足等式x2 + y2 + 7 = 4x + 4y,则x + y的值是多少?
整数x、y满足等式x2 + y2 + 7 = 4x + 4y,则x + y的值是多少?

整数x、y满足等式x2 + y2 + 7 = 4x + 4y,则x + y的值是多少?
x2 + y2 + 7 = 4x + 4y
x^2 - 4x + 4 + y^2 - 4y + 4 - 1 = 0
(x-2)^2 + (y-2)^2 = 1
x,y是整数的话,只能是 (x-2)^2 = 1 有 (y-2)^2 = 0 或 (x-2)^2 = 0 有 (y-2)^2 = 1
所以:x=3 或1 且 y =2
或 x =2且y = 3或1
所以 X+y = 3+2 =5 或 x+y = 1+2 = 3
答:x + y的值是5或3

(x-2)²+(y-2)²=1

(x,y)=(1,2)
(2,1)
(2,3)
(3,2)