原式=2*4+3*6=26
(x1,y1)·(x2,y2)=x1x2+y1y2,则(2,3)·(4,6)=
2个回答
相关问题
-
若x+2y=1 2x-3y=-1,则2x+4y-2/3 + 6x-9y/2=
-
【4】(-2x+3y)(-2x-3y) 【5】(-1/4x-2y)(-1/4x+2y) 【6】x^2+(y-x)(y+x
-
(1/3√x^2y)*(-1/4√y^2/x)/(1/6√x^2y)
-
若(x1,y1)•(x2,y2)=x1x2+y1y2,则(4,5)•(6,8)= ___ .
-
y=(3x^2-1)/(x^2+2) y=6/(x^2+x+1) y=4-根号(x^2+2x+3)y=2x+4根号(1-
-
1.x+1/2=y+3/4=x+y/5,则3x+2y+1/x+2y+3=?
-
若x+2y=1,2x-3y=2,则2x+4y-6/2+6x-9y/4=?
-
1.x-(3x-1)=5(x+2) 2.2(x+1)=1-(x+3) 3.20-y=6y-4(y-11)4.2-(4-y
-
1、若x^2+4x+y^2-6y+13=0,则x=___,y=___.2、已知x-1/x=3/2,则x^2+1/x^2=
-
(1)2X-Y=1 3X-2Y =1 (2)4X-3Y=11 2X+Y=13 (3)3X+Y=1 1/2X+1/4Y=0