原式=4*(-6)+(-5)*8=-64
(X1,Y1)·(X2,Y2)=x1x2+y1y2,测(4,-5)·(-6,8)=
1个回答
相关问题
-
若(x1,y1)•(x2,y2)=x1x2+y1y2,则(4,5)•(6,8)= ___ .
-
{x/3-y=5 (1) {x/4-y=1 (2) {5x+2y=5 (1) {2x+5y=8 (2)
-
【4】(-2x+3y)(-2x-3y) 【5】(-1/4x-2y)(-1/4x+2y) 【6】x^2+(y-x)(y+x
-
(2) y=(1-x)(1-2x) (4) y=(2+3x^2)√(1+〖5x〗^2 ) (8) y=log
-
已知样本甲x1 x2 x3 x4 x5 x6 和样本乙y1 y2 y3 y4 y5 y6 若x1-y1=x2-y2=……
-
1.8x+5y=10 8x-5y=10 2.3x+2y=9 4x-2y=5 3.2x+3y=5 6x-2y=-6 4.3
-
初中数学题1/4y=5y+1 7x+6=-6x 3/5y-8=1 -2x-3=-x+3 2x-1/8=x/7+1/2 -
-
计算:1/(x-y)-1/(x+y)-2y/(x^2+y^2)-4y^3/(x^4+y^4)-8x^7/(x^8+y^8
-
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
-
{y=3x-7{5x+2y=8{x-2y=3{2y+x=-1{2y-x=6{2x+y=8